The American Civil Liberties Union sued the small Eastern Shore town of Pocomoke City for $110,000 in federal court here today, contending its police have used an anti-loitering law primarily against blacks on downtown sidewalks to make the area "more amenable to white residents and tourists."

The seven-page suit claims that since last autumn, police have systematically ordered blacks to disperse from a popular intersection one block from Pocomoke City's main street and occasionally arrested black pedestrians.

The ordinance is rarely if ever used against whites, the suit says, and the police action amounts to selective enforcement against blacks, even when they are gathered quietly and not blocking the sidewalk.

"It's clearly racist and it's clearly unconstitutional," ACLU attorney C. Christopher Brown said in a statement issued here.

The suit asks the U.S. District Court to rule the ordinance an unconstitutional infringement of the right of free assembly and to award five black plaintiffs in the case $110,000 in compensatory and punitive damages.

The lawsuit met with immediate denials from officials of Pocomoke City, a quiet town of 3,800 near the Virginia border that won honorable mention in 1984 as an "All America" city by the Citizens Forum/National Municipal League.

The ACLU claims are "totally false," said town attorney John (Sonny) Bloxom.

"This town has never used its laws to discriminate against anyone," Bloxom said.

"I definitely would not agree with" the ACLU's lawsuit, city police Sgt. M. Lee Brumley said in a telephone interview. "Sure, we use it the ordinance if they're creating a disturbance . . . if there's some kind of fight or people using profanity . . . . But as far as going out of our way, we're not doing it."

Town boosters described Pocomoke City as a friendly community with a Campbell Soup factory and a clam processing plant as its economic mainstay. Signs posted at the city limits announce to motorists that they are entering the "Friendliest Town on the Eastern Shore."

Caught in the middle of the controversy is Keith Chesser, owner of Spide's fish market, a favorite hangout of some blacks that is located at Clarke Avenue and Willow Street, one block from Market Street, Pocomoke's main thoroughfare.

"Ninety percent of my trade is black people," said Chesser, who is white. But now I've lost 50 percent of my business."

The police objective, he said, "is to get the black people off the street. . . . We got a bunch of little dictators down here."

Chesser, who says he is "sixty-some years old," acknowledged that he sells "a lot of beer and wine" as well as fish but has had no difficulty since he bought the market in 1982.

"I leave my wife here sometimes all day long," he said, "and I've had no problems."

He said the intersection is a popular place for blacks not only to socialize but "to pick up odd labor, you know, construction work, clean out chicken houses, things like that."

The ACLU suit contends that police, on orders from city hall, have implemented a plan to "prevent black persons from standing on the public sidewalks" near Chesser's business.

The city fathers have concluded, the suit says, that "the presence of black people . . . is unsightly and has inhibited white people from shopping and venturing onto nearby Market Street."

Neither Pocomoke City Mayor Curt Lippoldt nor Police Chief Norwood C. Wimbrow was available for comment.

Brumley said there are several bars in the neighborhood that spawn disturbances, and police respond as needed. He said the loitering ordinance is used against whites as well as blacks.

Town attorney Bloxom acknowledged that parts of the ordinance, enacted in 1969, may be unconstitutional, such as sections that prohibit "loafing" and "walking about aimlessly without purpose." A unanimous 1972 ruling by the Supreme Court held a similar anti-loitering law in Jacksonville unconstitutional.

But Bloxom said there are other sections of the Pocomoke ordinance that are constitutionally sound, such as those prohibiting sleeping or obstructing free passage on sidewalks.

Police generally apply the ordinance only when a large congregation has blocked the sidewalk, Bloxom said, and a citizen has called to complain.

Bloxom also noted that Pocomoke's five-member City Council has a black member and three of the city's 11 police officers, including the second in command, are black.

"The people bringing this lawsuit are totally off the wall," Bloxom said.