A recent surge in the rate of Jewish emigration from the Soviet Union has raised the possibility of congressional action to grant tariff benefits and trade credits to both Moscow and Peking.

Rep. Charles A. Vanik (D-Ohio), the co-author of the most important legislative restrictions on these benefits for communist countries, said in an interview he thought Congress might be ready to approve removing them sometime this year.

Granting "most favored nation" tariff status and Export-Import Bank credits to China and the Soviet Union could result in better relations with both countries and a modest but significant improvement in the U.S. balance of payments.

"My feeling is that the Congress would go for it," Vanik said.

However, the recent sharp increase in Jewish emigration from the Soviet Union has made less of an impression on Sen. Henry M. Jackson (D-Wash.), also an author of the Jackson-Vanik amendment that precludes trade benefits to communist countries that unduly restrict their citizens' right to emigrate. According to aides, Jackson might not be upset to see China granted most favored nation status and Ex-Im Bank credits while the Soviets were denied those same benefits.

One of Jackson's associates said in an interview that if the United States was to effectively play the "China card" in its competition with the Soviet Union, then America would have to go further than simply recognizing the Peking government. This source suggested that the United States could even sell relatively advanced F4 fighter-bombers to the Chinese.

But others in Congress and the Carter administration who do not share Jackson's hard-line views on the Russians expressed dismay at the prospect that China might receive trade benefits that were withheld from them.

"That would be terrible," one White House official said, predicting grave strains in Soviet-American relatios if China got a symbolic and practical edge on the Soviets in trade with the United States.

"That could cause real problems," a State Department official contended.

The passage of Jackson-Vanik in 1974 plus adoption of a limit on Ex-Im credits to the Soviets of $300 million led Moscow to repudiate the previously negotiated Soviet-American trade agreement. That action ended the early, optimistic phase of Soviet-American detente.

In the four years since, Jackson-Vanik and the continued restrictions on Soviet-American trade have symbolized the superpowers' failure to make much of mutual value out of detente. The trade restrictions also bar the kind of extensive Soviet-American trade that Moscow apparently still hopes for as a means of coping with its substantial economic difficulties at home.

Late last year the Soviets apparently decided to take unilateral action to try to break the impasse in Soviet-American trade relations. They suddenly permitted a vastly increased rate of emigration by Jews, an apparent attempt to mollify supporters of Jackson-Vanik. Rep. Vanik said he thought Congress might indeed be mollified.

After a surge in the rate of emigration in the closing months of 1978, a total of more than 30,000 Jews was permitted to leave the Soviet Union last year. In the four previous years, emigration averaged about 16,000 pnnually. In 1973, the year before Jackson-Vanik was imposed, the Soviets allowed 35,000 Jews to emigrate.

The rate of over 30,000 "is higher emigration than exists anywhere in the developed world," Vanik said yesterday. "This is a dubstantial recognition... of the goals of the law [the Jackson-Vanik rider] and of human rights," he added.

"If emigration continues at that level," Vanik said, "I don't think it would be very difficult" to grant most favored nation status and credits to the Soviets. "My feeling is that the Congress would go for it."

"Going for it," Vanik said, would mean granting a "waiver" to the terms of Jackson-Vanik to both communist powers. The original amendment provides for such waivers if the president informs Congress that he has received assurances that granting trade benefits to these countries would promote freedom of emigration.

(Jackson-Vanik's restrictions apply only to "non-market" economies -- that is, socialist states. However, it does ano apply to Poland and Yugoslavia, which enjoyed most favored nation status before it was adopted, and waivers have since been granted for Hungary and Romania. Besides China and the Soviet Union, the amendment still applies to such countries as Czechoslovakia, Bulgaria, Albania and East Germany.)

Vanik promised to fight any attempt to alter or repeal Jackson-Vanik itself, which he compared to "the Bill of Rights -- it's part of the Law of the land."

The administration has taken the position that no attempt to alter Jackson-Vanik should be made until a new strategic arms agreement with the Soviets has been ratified. There has been no public comment from the administration on the idea of seeking waivers for China and the Soviet Union to grant them trade benefits.

The sudden recognition of China this month addedc a new element to these considerations. The Carter administration and the Chinese government obviously both hope for a large increase in their bilateral trade, but this would be most unlikely without credits and tariff benefits.

The Chinese would need large credits to finance big trade deals, and most favored nation status would significantly improve their prospects of selling goods in the United States. Present tariffs for Chinese goods that do sell in this country -- handicrafts, rugs, textiles and others -- are 40 to 90 percent and more higher than they would be under most favored nation status.

Although Jackson-Vanik was drafted primarily with the Soviet Union in mind, its terms clearly apply to China too, and China has also restricted emigration in the past.

Since the communists won the Chinese civil war, tens of thousands of Chinese have swum from the Mainland to the British colony of Hong Kong to seek asylum.

However, Chinese officials have recently demonstrated and discussed a willingness to relax controls on Emigration. At the same time, British officials have made it much more difficult for mainland Chinese to take up residence in Hong Kong.

An aide to Sen. Jackson noted that there is no phenomenon in China comparable to the Jewish emigration movement in Russia, and "the emigration situations are very different" in the two countries.

"If the Chinese are smart they would do what they could to create conditions to allow for a waiver" of Jackson-Vanik, this source on Jackson's staff said.

The United States has granted waivers of Jackson-Vanik to Romania and Hungary, two East European countries that have permitted substantial emigration, though in Romania, particularly, there are also continuing restrictions on the departure of unhappy citizens.