Most Americans know very little about their state and local courts, and the more they know the less confidence they have in them, a major national survey of public attitudes toward the court system shows.

While the survey found great public sentiment for reform measures, it also revealed that judges who run the courts, and to a lesser degree, the lawyers who practice in them express a greater degree of confidence in the court system.

"There is a significant gap, a difference of opinion, between the general public and community leaders - the consumers if you will - and the judges and lawyers on the other hand," said Arthur White of the nationally known public opinion research form of Yankelovich, Skelly and White Inc., which conducted the survey.

He said that gap is "unusual" and runs "much deeper" than in other institutions, including the differences between businessmen and their customers, which his organization has surveyed.

"Judges can no longer afford to take the lofty attitude that they are above it all," said Fred W. Friendly, who headed a task force that helped set up the survey, sponsored by the National Center for State Courts, which said it is the first study of its kind.

"They and the judical process will be measured by public opinion and will inevitably be challenged and changed by it . . ." continued Friendly, who is an adviser to the Ford Foundation on communications and a professor at the Columbia University Graduate School of Journalism.

The study found four major indications of public concern about the court system - delay in going to trail, the high cost of taking a case to court, high-priced lawyers and too few judges. Lenient bail provisions and sentences that were not tough enough also drew criticism.

TWhile the federal court system headed by the Supreme Court commands most of the headlines, the low public confidence in the state and local court systems is especially significant because they handle 95 percent of all the nation's judicial business.

The results of this survey - which Edward B. McConnell, director of the National Center for State Courts, termed "somewhat disquieting" - will be the focus of a four-day conference on the future of state courts.

The conference, which begins today with the dedication of the National Center For State Courts' new headquarters in Williamsburg, Va., will bring together the judges responsible for the court system; the lawyers who practice in it, and community leaders and members of the public who have expressed a low opinion of it. The center, a pet project of Chief Justice Warren E. Burger, is a private, non-profit organization founded seven years ago.

The Yankelovich survey showed that 45 percent of the public whose familarity with the courts was high had little or no confidence in the state and local court system. Only 18 percent of that group expressed a great degree of confidence, while 37 percent took what pollsters consider the middle ground by saying they were "somewhat confident" in the courts.

Even the people who acknowledged knowing nothing about the courts said they had little confidence in them. Or that group, 35 percent expressed low confidence while 27 percent said they felt confident in the court system.

One of the most startling findings of the survey was how little the American people know about the courts that handle their everyday legal problems - local crimes, divorce, wills and business and personal disputes.

Only 1 of every 4 persons polled expressed any knowledge of the court system, and that finding was backed by a kind of civics test about the judicial system. For example, almost 1 in 3 of the people who took the test thought the job of the district attorney - actually the government prosecutor - is to defend people who are accused of crimes but cannot afford their own lawyer.

In another conspicuous gap in the public's knowledge, not only of the court system but of this country's basic constitutional principles, almost 2 to 5 persons believe a person is guilty until he proves himself innocent - the exact opposite of the basic tenet of American criminal law that a person is innocent until proven guilty.

The poll also showed the public felt judicial decisions were influenced by political factors and that the poor and blacks were treated less fairly than the more affluent and whites.

Once more underscoring the sharp differences of opinion between the judges and lawyers on one hand and the public on the other, was the finding that judges almost universally said they treat averyone alike and their decisions are not influenced by politics. The opinions of the lawyers mirrored those of the judges, but to a somewhat lesser extent.

In another sharp split between the judges, lawyers and the public, the study found that community leaders and the general public thought the courts failed to take an active enough role in fighting crime - a position long held by police and prosecutors.

In addition to taking a greater role in reducing crime, the survey showed the public also expected the courts to be fair, to treat everyone equally and to shape up by cutting back on delays in going to trail and to reduce the cost of those who use the system.

In this context, the people surveyed thought there were not enough judges to handle the court workload and that lawyers charge far too much. Almost 1 in 4 persons surveyed feel lawyers ar more interested in themselves than in their clients, the study showed.

The public also showed great respect for judges and said it is far more important to find better judges than, for example, to build more prisons.

The survey showed the public was willing to try innovative new methods for changing the court system, including taking divorce cases out of the courts and expansion of court hours to nights and weekends. The people surveyed also said they would spend tax dollars to improve the court system.

Even though the vast majority of the people polled knew little or nothing about the courts, the pollsters said their views are significant because in the end it is the public who in manstates elects the judges and must ultimately approve spending more money on the courts.

What little knowledge the public has about the court system comes from formal education and the media, they study found, but there was great dissatisfaction with the way newspapers, magazines and television cover the courts.

The Yankelovich firm based its conclusions on four separate samples - 1,931 members of the general public; 278 community leaders such as businessmen, educators, politicians and civics organization and law enforcement officials; 194 state and local judges, and 317 lawyers.