In far Northeast and Southeast Washington - where six cab drivers were robbed, two shot and one killed so far this month - police have begun "tagging along" with some cabs and "spot checking" others, particularly those with young black male passengers.

"Basically, all were doing is spot checking cabs who we consider suspicious-looking," said Capt. Leonard A. Maiden of the seventh district. "I hate to get into what we consider suspicious."

Cabs have been singled out for scrutiny based on the "age, sex, number and very basic description" of the occupants, according to Insp. William R. Dixon, the seventh district police commander. Dixon said he has instructed his officers to follow cabs bearing two or more young black male passengers, and to look for unusual conduct on the passengers' or driver's part.

"At that point, or at some point during the trip, the officers pull the cab over for a spot check, and ask the passengers if they will give their names," said Nixon, who added that he has heard no complaints from either passengers or drivers about the procedure. "It's been emphasized to the officers that they've to be selective about whom they stop, and that the passengers are under no obligation to talk to them."

Approximately 100 cabs have been stopped during the last week, by regular patrol officers and special operations units detailed for the purpose, according to Capt. Fred Thomas of the robbery squad. Robbery squad detective have been sifting through copies of police "spot-check" forms, Thomas said and at least one promising suspect, still under investigation, has emerged form the process, he said.

Sixth and seventh district police have not had an easy time locating suspicious passenger groups, however, because drivers apparently have been shying away lately from young black men with destinations beyond the Anacostia River. One scout car spent three hours Tuesday night cruising the Oxon Run Parkway area, the scene of several recent taxi holdups, without spotting a single cab occupied solely by a male passenger or passengers. When police did follow one cab, occupied by a young couple, to an address on Livingston Terrace SE, the driver smiled, waved and flashed the "all-clear" sign as he collected his fare.

"There's some resentment from drivers," said Officer James Dodrill. "It costs them time and money, getting stopped, but most of the drivers and the passengers have been pretty cooperative."

Dodrill and his partner, Thomas Nelson, said they were unaware of any specific guidelines concerning which cabs to stop. "We short of play it by car," said Dodrill.

"They want you to let them know the reason why they're being stopped and to try to emphasize that it's basically for their protection," Nelson said. "It's not a form of harassment."

William J. Wright, chairman of the Taxicab Industry Group and of an emergency task force of industry, police and D.C. government officials named last week by Mayor Walter E. Washington, said yesterday that his industry supports the police program.

"It was kind of a mutual thing,' he said. "We've told the drivers to expect that they will be stopped.

City Council members Willie Hardy (D-seven) and Wilhelmina Rolark (D-eight), whose Anacostia districts have suffered the most taxi holdups, also voiced support for the increased police vigilance. However, Rolark said "it was never my understanding that they would be spot-checking somebody just because they were young, black and male."

Hardy, noting that her late husband had been a cab driver and once was help up, compared the program to the use of metal detectors in airports. "A lot of people who fly feel some discomfort," she said, "but a reasonable citizenry will accept that."

At a gathering of the mayor's taxi safety task force yesterday, the cab drivers, company executives and city officials hashed over assorted proposals for short and long-term security measures - most involving alarms, lights, bulletproof shields, and the wider use of two-way radios.

A vigorous debate developed over the value of bulletproof shields, which some drivers have purchased for prices in the $300-400 range. Many drivers, said Wright, "feel they can't communicate with the passengers . . . They feel like they're in jail."

Although there have been a rash of taxicab holdups here in September - 12 in all - the total for 1977 actually has been slightly smaller, so far, than it was for 1976: 70 this year compared to 79 at this time last year. "The amount of violence is what's different," said Capt. Thomas.