Egyptian President Anwar Sadat arrives in Washington Tuesday for his first meeting with President Reagan at a time of growing uneasiness among Egyptians over his policy of making peace with Israel without solving the Palestinian problem and his increasingly tough line against domestic opponents.

While no serious threat to his rule has appeared the Egyptian leader has lashed out at his critics with increasing bitterness and quashed potential centers of opposition as if he felt there was a far greater danger than is evident.

In the last few months, he has threatened to strip the small Socialist Labor Party, which he originally helped create, of its role as the official opposition, dissolved the leadership of the bar association for attacking his policies, tightened his control of the media and hinted at a crackdown on the activities of extreme rightist Moslem groups.

Sadat's actions have led some Western analysts here to question why he has become so nervous and whether more is going on beneath the surface than meets the eye. For the moment, most still doubt it.

But a growing sectarian conflict at home, which even he says has reached a "dangerous level," and likely rough waters ahead of him in dealing with the new Israeli government of Prime Minister Menachem Begin are regarded as causes for concern.

For reasons that remain unclear, Sadat has magnified the opposition as well as critics of his leadership at home and abroad by venting his rage about them in his speeches lately. For example, on the third anniversary of the founding of his ruling National Democratic Party July 11, he told the nation in a televised address about an ABC-TV report that drew some unfavorable comparisons between him and the late shah of Iran.

The party weekly, Mayo, subsequently published a text of the American television script thereby further publicizing what he regarded as unfair criticism of his rule.

Sadat decried the report as "all lies and falsehoods" and charged that an attempt was afoot by unnamed pressure groups, including hostile Zionists in the United States, "to embarrass me with the American people and the new administration" and to spoil his first meeting with President Reagan.

Had the Egyptian leader just ignored the report it would almost certainly have gone unnoticed by the vast majority of his people as well as the foreign media.

Sadat's manner of striking out at his critics at home has led some Egyptian observers to the conviction that he is giving the opposition more stature than it deserves.

"He is creating it himself," remarked one well-known Egyptian writer who asked to remain anonymous because of his delicate position in the government-controlled media. "Like Begin, he is his own worst enemy."

The official opposition leader, Ibrahim Shukri, whom few here took seriously before, confirmed the boomerang effect Sadat's tactics are having. He said there has been mounting sympathy and support for his Socialist Labor Party, which holds 17 of the 390 seats in parliament, ever since the president attacked it in a speech May 14, hinting that he might create another official opposition.

While government harassment of his party's deputies and supporters had greatly increased after Sadat's attack, Shukri said in an interview, "Our job among the people is easier and easier."

Shukri accused Sadat of wanting a facade of Western-style democracy but not the substance.

"He wants to say 99.9 percent of the people are all with him," Shukri commented. "At one time, he said he wanted other parties. That is good. But he must give an atmosphere in which you can have other parties."

Shukri particularly enraged Sadat, as did a number of opposition lawyers, by going to attend conferences and make speeches criticizing the Camp David accords. In April, he want to Damascus for the Palestine National Council meeting where, he said, he was careful not to attack Sadat or Egypt, but simply gave his party's backing to the Palestinian position on the accords.

"I spoke with the voice of many Egyptians," Shukri said.

"In the beginning, we were not against Camp David or peace," he said, explaining his party's position. "We are not against peace even now. But the results were not the ones we hoped for. We wish that our peace with Israel would go hand-in-hand with a solution to the Palestinian problem.

"Israel stopped completely on [the issue of] Palestinian autonomy. It even carried out some aggression against the Camp David process. Israel says this autonomy is for the people, not the land. This is just a new arrangement for ruling people. It's not real autonomy . . . We need a new plan."

Similiar criticism of the Camp David accords provoked a confrontation between the Sadat government and the lawyers' syndicate last month. Led by the chairman, Ahmed Hawaga, more than 100 members of the bar association staged a month-long sit-in at its headquarters to protest government efforts to toss out its board of directors.

Finally, Sadat last week got the parliament, which his party dominates, to pass a law formally scraping the board, decreeing new statutes for the association and appointing a new provisional leadership under a party faithful, Gamal Otteifi.

The lawyers' colorful strike and occasional demonstrations by the official opposition, like the one here in February at which the Israeli flag was burned on the first anniversary of Egypt's normalization of relations with Israel, have caught the attention of the foreign media and gotten considerable coverage. But neither the lawyers nor this fanfare is regarded by Western analysts as particularly dangerous to Sadat.

Less than 200 of the more than 40,000 members of the bar association participated in the strike, while public protests against the Camp David accords so far have failed to draw much of a crowd.

Far more serious to all appearances is the tension building between Egypt's minority Coptic Christian community of 3 million to 4 million and the majority Moslems. The biggest disturbance here since the January 1977 riots over food prices increases broke out June 18, when Copts and Moslems clashed violently for three days in a crowded, low-class district because of a land dispute.

Officially, 16 persons were killed and another 50 wounded. But local residents and foreign reporters who witnessed the disturbance said the toll was much higher.

Tensions in the Zawia al-Hamra district of Cairo remain high, with both sides reportedly wanting to take revenge for their dead. The government has kept a large force of riot police in the district to prevent any further violence and has also posted guards at the main Coptic cathedral.

While the clashes remained confined to Zawia al-Hamra and never took an antigovernment turn, the seizure of nearly 80 rifles and pistols, including some homemade machine guns, clearly has the authorities worried as to what might happen in the future.

In a speech last Monday, Sadat indicated that he, too, was deeply concerned, saying he thought the sectarian conflict had reached "a dangerous level." He has promised to disclose all the details of an in-depth investigation of the Zawia al-Hamra violence upon his return from the United States and to move to prevent a recurrence.

In what appeared to be a veiled warning to right-wing Moslem extremists, whom Sadat has so far treated gingerly, he said he would not tolerate the mixture of religion and politics in Egypt.

"A good example of this is Khomeini and how much he is letting religion interfere in politics," he said, referring to Iranian revolutionary leader Ayatollah Ruhollah Khomeini.