AFTER MORE THAN a decade of study, debate and compromise, the proposal federal criminal code will reach the Senate floor today. This code - known in its earlier versions as S.1 and Son of S.1 - is a monumental piece of legislaation. It touches almost every aspect of federal criminal law and deals with some of them in highly controversial ways. There are provisions in it that we don't like. Nevertheless, the code, with some improvements, deserves to be enacted.

The need for this general revision of the criminal law is clear. The laws now on the books are a collection of statutes passed at various times that bear little relationship to each other - sometimes, in fact, they conflict - and contain some provisions that are obsolete or arbitrary. Most of the bill now before the Senate is aimed at cleaning up this mess, a task never before undertaken.

The bill also would make some welcome changes in that law itself. The Smith Act, that abominable statute aimed at limiting freedom of speech, would be repealed. The system of sentencing would be altered drastically in a way that should reduce the present disparities in sentences imposed for similar crimes. The civil-rights laws would be expanded to include sex as well as race, religion and national origin. There are other areas of the law in which the bill is not so progressive. Some of these, like wire tapping, are so controversial that the writers wisely avoid entangling them in this omnibus bill be merely restating current law. In other areas, like obscenity and extortion, the bill would change the existing law in ways that unduly expand federal power. These sections ought to be amended, on the Senate floor or in the House, before the bill becomes law.

It is surprising that so long and complex a bill has been scheduled by Senate leaders for a relatively brief debate. They hope to vote on it by the close of business Friday. Behind that decision, however, lies the staok of compromises that this bill includes. No member of the Senate Judiciary Committee, which approved it by a vote of 14 to 2, likes everything in it. Some members think some of its sections are distinct threats to civil liberties; Sen. James Abourezk (D-S.D.) felt strongly enough about that to vote against the bill. Others think some sections are "soft" on criminals or too restrictive on the activities of law-enforcement officers, voted no on this account. How well the coalition of supporters, which ranges from Sens. Birch Bayh (D-Ind.) to James O. Eastland (D-Miss.), can hang together in the face of amendments on the Senate floor remains to be seen.

Credit for putting this package of compromises together goes largely to Sens. Edward M. Kennedy (D-Mass.) and the late John L. McClellan (D-Ark.). The 1971 report of the Brown Commission, out of which this bill grew, was regarded as a disaster by Sen. McClellan and others whose views on crime were like his.S.1, which was the Nixon administration's version of what that report should have recommended, waS regarded as as disaster by Senate liberals. Somehow, Sens. Kennedy and McClellan were able to negotiate out of the final bill many of the proposals one side or the other found most objectionable and to find compromises on many minor points of disagreement. What remains is an imperfect piece of legislation. It will not end or even reduce crime. It will not create an ideal set of criminal laws. It will not remove from the Senate the obligation to review in the near future some of those areas - like wiretapping - that are now being bypassed. But it will vastly improve the administration of criminal justice.