Secretary of State George P. Shultz, following a lengthy meeting today with Soviet leader Mikhail Gorbachev, said "deep differences" remain between the two nations, and he expressed doubt that even an "agreement in principle" on nuclear arms control can be reached at the U.S.-Soviet summit meeting in Geneva next month.

In a somber report at the end of 14 hours of intensive discussions, including nearly four hours with Gorbachev in the Kremlin today, Shultz said there had been "no narrowing" of the positions between the two sides on nuclear and space arms, the topic of current negotiations in Geneva.

Shultz said there were "some positive developments" in the talks, which are expected to be the last face-to-face exchanges at the top level before Reagan meets Gorbachev Nov. 19-20. Under questioning at a news conference, he declined to name the positive developments, which he suggested were limited to one or two matters of secondary importance.

Given the importance of the occasion -- Gorbachev's first business meeting with a top foreign policy official of the U.S. executive branch, and the closeness of the Reagan-Gorbachev summit -- Shultz's assessment was almost startling in its bleakness and its bluntness.

The prospect of a face-saving "agreement in principle" or some other way of minimizing fundamental differences at the summit, which have been proposed by Soviet Foreign Minister Eduard Shevardnadze, seemed to be receding. Shultz seemed unconcerned about the sharp differences that his report reflected and said there was "nothing surprising" in his talks with the Soviets. His intention appeared to be to lower worldwide expectations about the outcome of the summit meeting that have built up in recent weeks.

Asked about the prospects of success at the summit meeting, Shultz seemed to reduce his definition of positive results to the personal reactions of the two top leaders. "If they think things are unfolding, then it is a success," he said. At another point he remarked, "Life doesn't end in the middle of November," referring to the summit.

Shultz's meetings here during the past two days came at Soviet initiative, apparently because of Moscow's concern that the stage had not been set for a successful summit outcome.

Following today's meeting with Gorbachev and a quick lunch, Shultz met for an additional 2 1/2 hours with Shevardnadze. Afterward, he made a brief statement to reporters in the U.S. ambassador's residence and answered questions.

"We came here to exchange views, and we did so in a systematic manner," he said in the statement. "We anticipated a frank and thorough review of the issues, and that's what we had."

An official in the Shultz party said each side came to the meeting in Moscow with a draft communique, but these were "very different." He said, "They had a communique and we had a communique, and it was clear there was nothing in between." In the end, no draft statement was agreed upon.

In a brief announcement of the visit, the official Soviet news agency Tass quoted Gorbachev as saying he believed that if the summit passed in a constructive and businesslike spirit, it would help improve U.S.-Soviet relations and stabilize the world situation.

Leading up to Shultz's meetings here were a series of unusually sensitive incidents in Soviet-American relations. The most prominent, the "redefection" of KGB official Vitaly Yurchenko, was made public only hours before Shultz met Gorbachev.

On Monday, a Soviet soldier who had sought refuge in the U.S. Embassy in Afghanistan voluntarily returned to Soviet authorities after talking with Moscow's envoy in the Afghan capital.

Over the weekend, a Soviet sailor who jumped from a Soviet ship in Louisiana decided, after talking to U.S. and Soviet officials, to return to his crew.

Shultz said of Yurchenko that "the charges he has made are totally false." He said the case had been discussed "very briefly" in his talks with Gorbachev, and indicated that the United States, following its normal practices, will insist on hearing directly from Yurchenko that he wants to go home.

On the other hand, the Soviet decision to permit Yelena Bonner, the wife of dissident Soviet physicist Andrei Sakharov, to leave the country for medical treatment, improved the atmosphere for Shultz's talks, from the U.S. point of view.

The central issue, however, appeared to be nuclear arms control and especially the unrelenting Soviet opposition to Reagan's space-based antimissile defense plan, the Strategic Defense Initiative.

Shultz said the Soviets had given "preliminary" observations on the new U.S. arms proposals presented Friday in Geneva. By saying that "there was no narrowing" of the positions on arms issues, Shultz indicated that the Soviet reaction was far from positive.

An official in the Shultz party said that the Soviets did not back away from any of their previous positions on offensive or space armaments including intermediate-range nuclear forces, where there had been some hope for an early accord.

At the same time, the official said, the Soviets "gave the impression they really did want the meeting" in Geneva to be a success.

Regarding his meeting with Gorbachev, Shultz said there was "a vigorous discussion, . . . a very vigorous exchange" in which he and Gorbachev occasionally interrupted one another.

Asked how Reagan would contend with Gorbachev's blunt style, Shultz said, "The president is an old hand at this." He added, "It'll be a spectator sport."