Smiling broadly and speaking in halting Hebrew, Soviet human rights activist Anatoly Scharansky arrived to a tumultuous welcome in Israel tonight, fulfilling a 13-year dream that he said had sustained him during his years of imprisonment in a labor camp in the Urals.

As he nervously stepped out of a government executive jet onto the tarmac at Ben Gurion Airport, Scharansky was enveloped in a vigorous bear hug by Israeli Prime Minister Shimon Peres as a crowd of well-wishers sang "Shalom Aleichem," the traditional Jewish song of rejoicing.

The 38-year-old computer scientist, who walked to freedom earlier in the day across Berlin's Glienicke Bridge as part of an East-West prisoner exchange, told a crowd of several thousand cheering, flag-waving Israelis in an emotion-choked voice, "Brothers and sisters, people of Israel, during these years when I was in prison, these were very difficult days. There were years when I didn't receive a word from Israel.

"But there wasn't one day, even one minute, when I didn't feel a connection with all of you, even when I was in solitary confinement."

Scharansky's wife, Avital, who had not seen her husband since she immigrated to Israel just days after their wedding in 1974, clasped his hand warmly and beamed at the crowd, one of the largest ever to turn out at the airport for a welcoming ceremony.

Avital Scharansky, who had traveled throughout the western world seeking to bring political pressure to bear on the Soviets to release her husband, flew earlier in the day to Frankfurt to greet him and accompany him to Israel.

Peres, using the Hebrew name that Scharansky has adopted as a new immigrant to the Jewish state, said, "Welcome, hero of Israel, Natan, to your country, your homeland and your people. Gentlemen, today Natan, tomorrow Ida Nudel [another refusednik] and all the prisoners of Zion to their country and their homeland. The Jewish people will live."

Earlier, Peres and the Scharanskys talked by telephone with President Reagan from an airport reception room. Scharansky told Reagan, "I know how great was your role . . . in the fact that I could join my people. As you know, I was never an American spy. Please inform all your people of our deepest gratitude."

After the reception rally at the airport, the Scharanskys went by car to Jerusalem to pray at the Western Wall, a remnant of the Second Temple, which for two millennia has been a focus of the Jewish people's longing to return to the capital of the ancient Hebrew nation.

There, thousands of Israelis jammed the broad plaza below the Old City's Jewish Quarter in one of the biggest outpourings since the Israeli Army captured East Jerusalem in the 1967 war. They sang and danced as the released Soviet prisoner was carried on the shoulders of well-wishers to pray at the holy site.

Although Scharansky's release held special significance for Jewish human rights activists here as a symbol of the struggle on behalf of Soviet Jewry, Israeli immigration officials and leaders of Soviet Jewish organizations expressed doubts that it would have any practical effect on the Soviet Union's emigration policy.

Despite persistent rumors of an imminent relaxation in Moscow's policy on issuing exit visas, Jewish emigration last year was only 1,140 -- compared with 51,000 in 1979 -- and Israeli officials say they see no reason to be optimistic about any immediate increase.

Jewish emigration in January fell for the second straight month, with only 79 arrivals registered at the Vienna transit center.

"Obviously the fact that Scharansky has left is important, because he is not just another refusednik," said Gad Ben-Ari, spokesman for Israel's Ministry of Absorption. "He is the most important symbol of prisoners of Zion. However, his exchange is not being presented by the Soviet authorities as a sign of a new policy, not explicitly or implicitly."

Ben-Ari added, "We haven't seen any indication whatsoever of a shift in policy, or for that matter, even in gestures. The figures speak for themselves."

However, Ben-Ari said, Scharansky's decision to come immediately to Israel could have a positive effect -- from Israel's viewpoint -- on the dropout rate of Soviet Jews permitted to leave for the Jewish state. Of the 260,000 allowed to emigrate since 1967, more than 100,000 went to the United States and Canada, creating a "brain drain" problem as well as sending a potentially volatile message to other religious and ethnic minorities in the Soviet Union.

Of the 79 Jews who left the Soviet Union last month, only 19 went to Israel, and the rest went to Rome to get papers for other countries.

"We hope Scharansky's immigration here will have a positive effect on other refusedniks who might be considering dropping out along the way," Ben-Ari said. "We believe that if the time comes when the gates are opened there should be an arrangement which will make direct flights for Soviet Jews to Israel easier."

Uri Stern, director of the Soviet Jewry Information Center, said the prisoner exchange was "a sign that they could make a change in their policy, and that is what is important to us."

Stern added that his movement would seek more releases "by pressure and by making it very clear that they can't go forward with trade and scientific exchange, or with better public relations or political relations without a change in their policy toward the Jews."