The Justice Department has approved a $734,371 study of Playboy, Penthouse and Hustler magazines to determine whether they play a part in juvenile delinquency or sexual exploitation of children.

The review is a slightly scaled-down version of a $798,531 study that was to have included nonsexual magazines and other literature. That study was approved in December 1983 but has been virtually on hold since late last year because of congressional criticism.

The revised project will include a review of all 660 issues of Playboy, Penthouse and Hustler published through last December.

It is being conducted by Judith Reisman, a former songwriter for the "Captain Kangaroo" television show, and is based at the American University School of Education, which has hired her temporarily to run the project.

She was not available for comment yesterday.

A project official, who asked not to be identified, said yesterday that there are now seven full-time employes handling the study, along with 12 part-time data analysis personnel.

According to the Justice Department, issues of particular concern include:

* "Sexual depiction of children with fairy tale characters and themes such as Santa Claus, Dorothy and the Wizard of Oz, Snow White, etc."

* "Children involved sexually with 'influential' adults (member of government, police officer, doctor, teacher, counselor, military personnel, member of the clergy, etc.)."

* "Use of child paraphernalia, including teddy bears, hair bows, bobby sox and dolls, in cartoons, as well as pictures depicting adult women as 'pseudo children.' "

The original study was approved by the department's Office of Juvenile Justice and Delinquency Prevention and authorized to continue for 22 months.

But it ran into a storm of congressional criticism after a project analyst in the office said that the project could be completed for $60,000. Reisman was called before a Senate committee to defend it, and other officials testified before a House committee.

Anne Voigt, a spokesman for the office, said yesterday that Reisman submitted the revised project design in January and that it was approved in the past two weeks.

She said that the project was revised not because of the congressional criticism but because "so much time was spend responding to Congress that we felt the scope needed to be reduced to give her time to come up with a finished product."

Voigt said that $194,445.93 of the original grant had been spent by the end of last year. A Justice Department description of the project said that $153,083 of that amount was required "to revise design and respond to numerous requests from press."

Voigt said that the three magazines were chosen for the revised study because "they have the largest circulation and are the most well known of the sexually explicit publications."

"This genre reaches millions of adults and juveniles each month, many of whom read erotica/pornography at home," the project description said.

The project is scheduled to be completed in November, but Voigt said a no-cost time extension probably would be allowed if necessary.

The project official who declined to be identified said yesterday that the group plans to look at all issues of the magazines, dating to 1953 for Playboy, 1969 for Penthouse and 1974 for Hustler.

"By analyzing the extent and nature of mainstream erotic/pornographic content, with special focus on child imagery, this research may be said to lay the foundation for future studies on the possible influence, or lack of influence, of erotica/pornography, with particular emphasis on issues of child exploitation: molestation, prostitution, incest, kidnaping, general juvenile delinquency and child pornography," the project description said.

Reisman said in the written description that if time allows, she plans to analyze "a random sample of all published letters to the editors and advice columns, with particular attention to the discussion of children in sexual, criminal or violent activity."

Reisman has grown children and received a doctorate in communications studies from Case Western Reserve University in Cleveland in 1980.

Her resume includes a number of positions connected with children's television.