Education Secretary Terrel H. Bell yesterday proposed canceling a federal regulation on public school dress codes, saying it put the government in the "absurd position of spending investigators around the country to check on the length of boys' hair or girls' see-through blouses."

The regulation says school districts will lose federal funds if they "discriminate against any person in the application of any rules of appearance." The regulation has been on the books for almost six years but has been sporadically enforced.

Bell said that if he didn't move to change the federal rule, civil rights officials in his department told him he would have to cut off funds to 50 districts throughout the country where discrimination complaints had been found justified, mostly because their dress codes prescribe different hair lengths for boys and girls.

"I just couldn't bring myself to sign those letters threatening to cut off funds," Bell said. "I don't think the federal government has any business getting involved in these local squabbles. Decisions like this are rooted in community standards. It's not something that should be done on the national level."

Before the rule is actually rescinded, Bell said, a 60-day period for public comment must elapse. He said he expected the regulation to be finally gone by early summer after bedeviling federal officials and local school systems for half a decade.

In late 1978, former health, education and welfare secretary Joseph A. Califano Jr. proposed rescinding the rule for most of the reasons that Bell gave yesterday. But Califano was fired by President Carter before the rescission went into effect. His successor at HEW, Patricia Roberts Harris, reversed Califano's move, stating that "discrimination that stems from appearance codes can be as seriously damaging and demeaning as other types of discrimination."

Harris' action received strong backing from the National Organization for Women's Project on Equal Educational Rights. But before Harris could begin the vigorous enforcement she promised, the HEW department was split and the new Education Department took over responsibility for the rule.

Yesterday a department spokesman said the regulation had been in limbo during the last months of the Carter administration.

The rule was first issued in 1975 by Caspar Weinberger, HEW secretary under President Ford, to implement Title IX of the 1972 Education Amendments. Title IX bans sex discrimination in schools and colleges.

Bell was U.S. commissioner of education when the regulation came out, but the rule was prepared by a separate section of HEW, the office for civil rights, and Bell said he was not consulted beforehand.

"It's a frivolous rule at best, but it's worked out to be an absurdity," Bell said.

"I just don't think these are civil rights that we should solemnly enforce," he said. "If people are being discriminated against, they have courts to go to. But every time a high school principal gets into a ruckus about the length of somebody's hair or a girl without a bra, they shouldn't be able to get us involved."