Congress appears to be going along with President Carter's admonition to hold the fiscal 1980 federal budget deficit below $29 billion-but with somewhat different priorities than the president proposed.

The Senate has approved initial congressional budget targets that call for outlays of $532.6 billion and a red ink figure of $29 billion, with only minor changes from the spending plan Carter presented in January.

Next week, the House will begin debate on a counterpart resolution calling for a $28.4 billion deficit-though with a significantly lower defense figure and changes in other key Carter programs.

While it still is too early to tell how these differences may come out in conference committee, it's clear the lawmakers are austerity-conscious this year. All that makes it likely that Carter will win the bout.

The Senate action this week was relatively disciplined, at least by that chamber's standards. The senators defeated a spate of amendments that would have altered the budget totals sharply, approving only a few changes.

The battle in the House, however, promises to be fever-pitched-with Republicans seeking to boost defense outlays while cutting overall spending, and liberals hoping to "restore" funds for several key social programs.

Observers say there is more than an outside chance that the House might defeat the budget resolution the first time around. In that event, House leaders would have to seek a compromise measure.

Approval of a joint House-Senate budget is part of the five-year-old congressional budget process, which Democratic leaders established in the mid 1970s to give Congress a better grip on its own purse strings.

Under the new procedures, the two chambers must agree on preliminary spending and taxing targets by May 15. They review them in mid-September, and transform them into binding spending ceilings.

The handful of changes made by the Senate this week involve restoring modest cuts recommended earlier by its Budget Committee in areas such as Social Security benefits, food stamps, disaster relief and nutrition.

James T. McIntyre, director of Carter's Office of Management and Budget, praised the lawmakers for "responsible restraint." He said that while the White House disagreed on some priorities, the resolution "supports" Carter's anti-inflation effort.

In addition to the fiscal 1980 targets, the Senate's resolution also calls for balancing the budget in fiscal 1981, running a $600 million surplus that year and a $900 million surplus in fiscal 1982.

However, the goal makes the assumption that Congress will not cut taxes again until after the 1980 election-a restraint most observers regard as unlikely. The House resolution does not include goals for fiscal 1981 and 1982.