A crowd of 600 people sought last night to persuade Prince George's County Executive Parris Glendening of the need for budget items ranging from education to school athletics to low-cost housing in the face of predictions of a $35 million deficit.

It was the first public hearing held by Glendening, a Democrat elected by a landslide last November. He had invited a large turnout by sending out more than 2,000 letters to elected officials and various community leaders, saying their views "will strongly guide me as I make the difficult policy decisions required to balance the county budget."

More than 150 people representing a variety of groups signed up to speak, and Glendening took the opportunity to outline the county's fiscal predicament.

By encouraging attendance at the hearing, held in the 800-seat auditorium at Eleanor Roosevelt High School in Greenbelt, Glendening was also attempting to distinguish hmself from his predecessor, Republican Lawrence J. Hogan, who was the first executive to hold public hearings before preparing the budget.

Hogan, forced to hold the hearings because of a law passed by the Democrat-controlled County Council, used a small fifth-floor conference room in the County Administration Building in Upper Marlboro. Those testifying waited in a basement cafeteria and were escorted upstairs when their turns came.

Glendening started last night's session with a half-hour budget presentation, saying the county would have only $2 million in new revenue to pay for between $25 and $50 million in budget requests. He said he is depending on the state legislature to help him find new sources of revenue, but without that assistance he said the county would have to reduce services and deny public employes cost-of-living raises.

Then the speakers, who ranged from labor representatives to grade school pupils, offered a wide variety of views on budget priorities.

Joseph Anthony, mayor of the town of Colmar Manor, said the county should cut its share of the budget of the Maryland-National Capital Park and Planning Commission. "There's got to be some fat there," he declared. He suggested more money for education and for more shelters at county bus stops.

Board of Education Chairman Susan Bieniasz was one of more than 50 people who spoke strongly in favor of additional school funding, particularly in light of last year's layoffs of 507 teachers. "We don't need to hold the line this year," said Bieniasz, "we need to get some of those programs back. . . . We have a county crisis and a crisis that's right at the door of public education."

Other departments pressed their causes, too, particularly representatives of public safety workers. Mahlron Curran, president of the county's Fraternal Order of Police chapter, and firefighters union leader Ronald Milor described problems their departments are having in fielding enough people to respond to calls. A representative of the county's medical society spoke along the same lines, saying the county needs more mobile emergency medical units than its present three.