The Central Intelligence Agency yesterday discouraged any idea that a new U.S. Soviet strategic arms agreement would enable both superpowers to reduce defense spending.

"Conclusion of a SALT II agreement along the lines currently beign discussed would not, in itself, slow the growth of Soviet defense spending significantly," predicted the CIA in the unclassified version of a report submitted to the Joint Economic Committee.

Since the Carter administration has repeatedly pledged to keep up with the Soviet Union militarily, the view from th CIA is for higher and higher defense budgets in both nations, strategic arms agreement or not.

While, the CIA's assessment may give ammunition to critics of the strategic arms limitation talks (SALT), President Carter has based his pursuit of a SALT agreement not on saving money but on making the world less dangerous by reducing the nuclear arsenals commanded by Washington and Moscow. Therefore, his pursuit is expected to continue.

Even though the Soviet economy is in no great shape today and will slow down further in the 1980s, the aid in its 14-page report, "all of the evidence available to us on Soviet defense programs underway and planned suggests that the long-term upward trend" in Moscow's military spending "is likely to continue into the 1980s."

From 1967 to 1977, the agency said in its report, Soviet defense spending increased by about 4 to 5 percent a year, taking between 11 to 13 percent of the gross national product and absorbing about one-third of the metal industry's output.

"There is no indication that economic problems are causing major changes in defense policy," the CIA said, although "modest atlerations" may be under consideration.

Like the United States, the Soviet Union spends most of its defense money on nonnuclear forces - the troops, tanks, ships and artillery for World War II-type warfare. They would not be covered under a SALT agreement and thus would continue to drive up Soviet military spending, barring some negotiated limit on nonnuclear forces.

"Spending for intercontinental attack forces subject to SALT II limitation consistuted a little over 10 percent of total defense spending and grew at a slower pace than the total," the CIA said in assessing Moscow's 1967-77 outlays.

In that same period, Soviet nervousness about both their front and back doors was reflected in CIA estimates that the Kremlin doubled its spending for forces along the NATO and Chinese borders.

The CIA, in this latest of several reports on Soviet defense spending, tried to pick out the significant trends. It did not make any direct comparisons with U.S. spending.

In assessing the 1967-77 period and analyzing what is likely to happen next, these were among the findings:

Soviet bomber. "The Soviets may also be developing a new long-range bomber. If such a bomber were to be deployed, it could be introduced into Long Range Aviation units by the early 1980s."

SALT impact. A strategic arms control agreement along the lines proposed by the Carter administration "Would probably reduce the rate of growth of total Soviet defense spending by only about 0.2 percentage points per year. The resulting savings would amount to less than 1.5 percent of total defense spending projected through the early 1980s in the absence of an agreement.

Soviet anti-submarine warfare (ASW). "The Soviets probably will give a greater priority to the open-ocean ASW mission and to increasing production of nuclear-powered attack submarines . . . Continued procurement of the Backfire bomber is also lilely, and introduction of a new long-range ASW aircraft is possible . . ."

Soviet research. "The resources allocated" to military research "will continue to grow into the 1980s."

Cruise missile defense. "By the early 1980s we expect deployment of new low-altitude, surface-to-air missiles and one or more modified interceptors designed to engage low-flying targets", like the cruise missile President Carter has decided to build for the 1980s instead of the B1 bomber.

William Perry, Pentagon resarch director, has said the Soviets' greatest weakness in defending against the cruise missile is lack of "look-down" radars. The CIA said "the Soviets will probably deploy new ground-based, air-surveillance radars and airborne warning and control aircraft. These aircraft carry look-down radar.