Some 1,500 school employes, most of them teachers and librarians, would be laid off in Prince George's County, if County Executive Lawrence J. Hogan's proposed 1983 budget is approved, according to an analysis by the County Council staff. County and school officials said these would be the first widespread firings in the school system's history.

Although council members said they were dismayed by the situation, they were reluctant to consider cutting the county budget in other areas during a work session yesterday.

The analysis details the impact of Hogan's proposal to cut the schools' budget $7.3 million from the current year's funds and some $37 million from the school board's request. Hogan's budget gives $300.9 million to schools in fiscal 1983, which begins July 1. Hogan has said repeatedly that he considers the board's request to be unreasonable.

Hogan said few layoffs would occur under his budget, which would not pay for salary increases contained in a recently negotiated teacher's contract. He wrote, "Considering that the board annually experienced heavy turnover in certified personnel and custodians, there is reason to believe that very few reductions in force will result if my recommendations are implemented."

According to the council staff's analysis, layoffs would be necessary if the board insists on funding the already negotiated teachers' contract, which includes a cost-of-living increase and a dental plan.

Although the analysis represents only one version of the possible cuts, assistant school superintendent Elliot Robertson said, "I'm not going to quibble over every line because the problem is too big for that."

Budget director Robert Duncan, whose office prepared the budget under Hogan's direction, said he disagreed with the council about the size of the potential layoffs, but said he did not have an estimate himself. However, he said the figures used by the council staff in its analysis matched his own.

Many council members said that they realized for the first time yesterday the magnitude of the county's fiscal constraints. "I guess I kept hoping that someone would find that there were other ways to divert (money) . . .so that so many people wouldn't be affected," said Councilwoman Ann Lombardi, in the past a staunch defender of school spending. Lombardi, who previously criticized increases in police and fire budgets at the expense of education, said she now believes that the public safety increases are crucial.

School union officials reacted to the possible layoffs with anger. Frederick C. Rummage, executive director of the Prince George's County Educators Association, said, "Our priority is the three employes contracts. What we want to do is get our heads together with the board and decide what proposals, if any, are acceptable."

The council must pass its version of the county budget by June 1.