Partly on purpose and partly because it could do no better, the 96th Congress passed relatively few important bills its first session, which wound toward a close last night.

The Senate approved the Panama Canal treaties. Also approved were a trade bill, standby gasoline rationing, energy aid for the poor and bills to create a Department of Education and bail out Chrysler Corp. And Congress voted itself a pay raise.

But most other bills of consequence were left to be acted upon -- or not -- next year.

All three of President Carter's energy proposals remained in House-Senate conference committees: his controversial tax on oil, the bill to create an energy mobilization board to run regulatory interference for major energy projects and a bill to subsidize production of synthetic fuels. Also in conference was the bill to deregulate the banking industry and let banks and savings and loan association offer small savers higher interest rates.

The House has passed -- but the Senate has not -- a bill restructuring the welfare system, another increasing aid to higher education, an Alaska lands bill, a bill restricting campaign contributions by poliitical action committees and a bill to shorten the reach of the Federal Trade Commission.

By contrast, the Senate has passed -- and the House had not -- a bill revising the federal criminal code and another rewriting the rules for regulation of drugs.

The Senate postponed action on SALT II, partly for lack of the necessary two-thirds majority.

But partly to win votes for SALT, the president proposed -- and Congress agreed -- to increase future defense spending sizably.

House and Senate agreed on a budget for this fiscal year, but were a month late in doing so and still have not passed all the basic appropiations bills. Some units of government are operating under a so-called continuing resolution.

The House voted down the president's hospital cost containment bill for the second year in a row; the administration will try next year to revive some form of it in the Senate. The House also bowed to consumers and killed a bill raising sugar price supports. But a milk price support bill was passed.

Congress also passed legislation to sustain the traditional U.S. relationship with Taiwan even while recognizing the People's Republic of China.

Congress was cautious by design. Its indecisiveness and unwillingness to venture much reflected a national mood. It also reflected rising inflation, and a reluctance to increase either government spending or government regulaltion of people's daily lives.

Carter sent fewer proposals to Congress than in his first two years in office, and leaders predicted early in the year this would be an "oversight Congress." It largely was.

The welfare "reform" bill passed by the House would expand the existing program somewhat. The House-passed higher education bill would allow a 50 percent expansion of that program.

Elsewhere restraint was the watchword. Neither house acted on national health insurance, the one large new domestic program discussed in recent years, though both houses had committees at work on the issue.

Even on many bills it finally did pass, the session of the 96th was hesitant. It took several tries to pass standby gasoline rationing, the budget and even the pay raise.

The big question mark now is how Congress will perform next year, whether it will pass those bills now at various stages in the mill, or be so distracted by election year politices and the unevenness of the economy that it will leave many bills to die. All bills unpassed in this session retain their present status next year; Congress does not have to start over.