he only class struggle in Beidaihe is for the prime crabs.

For this is China's most famous seaside resort, a stretch of paradise far removed in character from the rest of the country and set aside for communist leaders to enjoy the good life the average worker only dreams of.

Except for a few rest homes for blue-collar laborers who do high-tension work, Beidaihe is a warm-weather refuge for a class of party cadres, government officials, military officers and their children with the most treasured privilege in today's China--THE VACATION.

They board the bunk-bed cabins on the fast train in Peking and ride 170 miles due east to Beidaihe, then check into the stucco villas and bungalows that foreign diplomats and missionaries built in the early 1900s for relief from the hot cities.

Once here, the serious Chinese officials melt into carefree leisure, trading their drab Mao suits for bright shirts and straw hats.

Not far from the crowded, sweltering cities of northeast China, sunbathers dip into the cool waters of Bohai Gulf. After the sun drops behind rounded hills, they stroll past fragrant fruit trees and dine on crabs and chocolate sundaes.

The early bird gets the biggest crab, hefty creatures brought at dawn by fishermen who cruise their boats to shore. At 5:30 a.m., dozens of Chinese are shopping for their dinner, buying seafood that they present to restaurants for storage and later preparation.

By 9 a.m. the most dedicated sunbathers settle down on the sandy beach, chasing away the seashell hunters who arrived hours earlier. The new settlers come fully clothed, sometimes carrying suitcases, and manage to slip into bathing suits without a single indiscretion.

There are no bikinis among the Chinese smart set. For women, the attire is a one-piece, puckered cloth suit that comes in green, red and blue. Men display even less variety, sporting the standard brief. It comes in black.

The beach curiously reflects strains within Chinese society itself. Accustomed to crowded neighborhoods and work places, the bathers congregate tightly in certain areas, leaving open large stretches of sand.

Many Chinese outfitted in swimsuits stalk the shoreline under large umbrellas, afraid that the sun will turn their skin as dark as the humble peasant's--the Chinese version of a redneck. Others roll in the sand like colts in a meadow, claiming that the warmth relaxes their muscles.

Aside from the popsicle vendors, a main attraction for Chinese beach-goers is the few dozen foreigners who lie together in what had until recently been restricted to non-Chinese. Hairy-chested Western men and bikini-clad women are enough to keep some gazers busy for hours.

Then there are the photography fanatics. Young women with elaborately coiffed hair and heavily made-up faces pose on rocks or half submerged in water as their boyfriends snap away. For the unprepared, professional photographers rent swimsuits and take pictures for less than $1.

Nightfall turns Beidaihe into a quiet village. Unlike Western resorts, there are no bars or nightclubs, bingo games or miniature golf. The evening's activities normally center on dinner, and the most popular place in town is Kiesling and Bader.

At this restaurant once run by Germans, Chinese vacationers dine under the stars and trade in their chopsticks for knives and forks. The specialty is seafood, topped off by a chocolate sundae served in huge silver goblets.

As if going to a masquerade party, 10 Chinese teen-agers donned Western suits and floor-length dresses for dinner at Kiesling and Bader one recent night. Leaving the restaurant, they took turns photographing each other standing below the small neon sign outside.

"Ladies and gentlemen, step right this way."

The crowd drew around a short, pock-faced man who opened his sideshow act by swallowing an apple-sized metal ball and then regurgitating it. After a few more feats too painful for most of his audience to watch, he inserted four-inch metal nails into his nostrils and passed around a felt hat for tokens of appreciation.

The performer was the center of attention in what passes for Beidaihe's midway, a diamond-shaped city park planted in the middle of a small commericial sector.

The park looks more like a flea market than an oceanside boardwalk, but it nevertheless adds enough honky-tonk to make Beidaihe respectable as a resort town.

Merchants setting up their wares on small crates hawk everything from seedless grapes to seashell kitsch. A clothier drapes slacks and skirts over a long line stretched between two trees. Under an elm, a young man displays his collection of homemade, plaster of Paris figurines: Greek statesmen wrapped in togas, panda bears and Jesus Christ statuettes. But there are no Chinese historical characters.

"Do you have a bust of Chairman Mao?" he was asked.

"No," he replied, picking up a mold of a reclining Buddha. "Try this. He's a smart man."

Even if they had the time off, few Chinese could afford Beidaihe.

A bed in one of the dormitory-like hostels can run as much as $2.50 per day. Meals can absorb a few dollars more (crabs sell for 90 cents per pound).

That puts Beidaihe out of reach for the average Chinese urban worker who earns $35 a month.

At first glance, Xiao Yang seemed the curious exception. A schoolteacher from the poor province of Shanxi who takes in less than $25 a month, she had settled in for a week's stay.

How can she afford the costly life?

"I saved the money, a little every month," she said.

How do her small savings cover the expense?

"My father helps," she explained finally. "He has a good job at the Foreign Ministry."