The body of Commerce Secretary Malcolm Baldrige was flown to his home town of Woodbury, Conn., yesterday after an autopsy showed that he died after his chest and abdomen were crushed in a freak horse accident.

In a traditional cowboy tribute, the horse that flipped over on Baldrige Saturday afternoon was led riderless Saturday night around a rodeo ring in California where Baldrige had planned to perform.

The crowd stood and sang "God Bless America" and the national anthem as statements of shock and sadness poured in from President Reagan, Vice President Bush, congressional leaders, friends and the Japanese minister of international trade and industry.

A memorial service is planned at 10 a.m. Wednesday at the National Cathedral, with Sen. John C. Danforth (R-Mo.)., an Episcopal minister, presiding. The funeral will be in Woodbury at the North Congregational Church the next day.

Baldrige had flown to California to participate as a special contestant in a rodeo with his friend and roping partner, Jack Roddy, on whose ranch east of San Francisco the accident occurred.

"About 1:10 Saturday afternoon {PST} Baldrige had just successfully roped the heels of a calf and had just released the rope," according to Bert Kreitlow, a reporter for the Pittsburg (Calif.) Post-Dispatch, who was watching. "The horse backed up a couple of steps, stumbled and flipped over. Mr. Baldrige never got off the horse."

The horn of the saddle struck a "very large belt buckle that was on his abdomen," according to Dr. Ronald LaPorta, a trauma surgeon and chief of surgery at John Muir Memorial Hospital. The horse's full weight of approximately 1,200 pounds landed on Baldrige.

Wally Partridge, a volunteer firefighter from a nearby town, and Dr. Bert D. Johnson, a Stanford University gynecologist, attempted cardiopulmonary resuscitation.

"When I first got there he had no pulse, no respiration," Johnson said.

Kreitlow said Baldrige "was delirious and moaning softly, mumbling, 'Please let me sit up.' The cowboys stood around silent, some holding their hats out to shade him" in the 80-degree heat.

Baldrige was flown to the hospital by helicopter, but surgeons could not control the internal hemorrhaging, LaPorta said. "His blood pressure slowly crept down and he eventually had cardiac arrest."

Dr. Ervin Jindrich, called in from nearby Marin County because the Contra Costa County medical examiner was away, performed an autopsy and concluded that Baldrige had died from a "crushing thoraco (chest) abdominal injury."

Tributes poured in yesterday. Vice President Bush said, "Mac Baldrige set the standard for excellence, decency and integrity in public life. He was a tower of strength and truly a man of honor."

Japan's minister of international trade and industry, Hajime Tamura, said Baldrige's death was "an immeasurable loss" to U.S.-Japanese relations.

Clarence J. Brown will be acting secretary until a successor to Baldrige is chosen. Brown, a former GOP congressman from Ohio, has been deputy commerce secretary since 1983.

Baldrige is survived by his wife, Margaret Trowbridge Murray, and two daughters, Megan Brewster Murray of New Mexico and Mary Trowbridge of New York. Also surviving are one sister, Leticia of New York, one brother, Robert of Long Island and two grandchildren, Malcolm and Fonda Murray.