For the dead whom few wanted to remember after a war few could forget, a woman who was 4 years old when the first bodies came home has designed a national memorial to be built on the Mall.

Maya Ying Lin, who is 21 and a Yale undergraduate architecture student, was picked out of 1,420 entrants as winner of a competition sponsored by the Vietnam Veterans Memorial Fund.

"I liked my idea but I knew it was never going to be chosen -- it was too different, too strange," said Lin, whose parents emigrated from China in 1948 and teach at Ohio University.

The memorial design shows two polished black granite walls, each 200 feet long. They meet to form an oblique triangle. Inside the triangle the ground falls away at a five-degree slope until it reaches the apex. There, the walls will be 10 feet high. They will be inscribed with the names of the 57,692 Americans killed in Vietnam between 1963 and 1973. The names, in letters 3/4 of an inch high, will be listed in chronological order of death.

Said Lin: "These names, seemingly infinite in number, convey the sense of overwhelming numbers, while unifying those individuals into a whole. For this memorial is not meant as a memorial to the individual, but rather as a memorial to the men and women who died during the war, a whole."

Her design does not mention the war itself, or the Republic of South Vietnam; only the names of the dead.

Washington architect Paul D. Spreiregen, who served as a professional adviser to the memorial fund, quoted one of the jurors as saying: "In a city of white memorials rising, this will be a dark memorial receding." He said the jury, composed of two architects, two landscape architects, three sculptors and an architectural editor, had decided on a minimalist design because "people can bring to it whatever they want."

Said Lin: "The design sort of popped into my head. I wanted some sort of journey into the earth."

She submitted it as part of course work in funerary architecture at Yale. Both she and her professor entered the contest. The professor gave her a B in the course. She won the $20,000 first prize.

Asked for her memories of the war, she said: "It didn't enter my world. I remember there were riots, and my parents would never let me out of the house when thee were riots. Later on the realization of the youth of the people involved came to me -- that they'd been killed in the war or while protesting."

Asked about the fact that neither the war nor the country it was fought in is mentioned in the design, Robert Doubek, project director, said: "Does Washington's name appear on the Washington monument? You would have to be very oblivious to reality to not know where they died."

Doubek said that "one of the [submitted] designs had a big peace sign on top of it, but there were very few with political messages."

With 1,420 entries, requiring an estimated 80 man-years of work, this was the biggest design competition in the history of this country, Doubek said. "I was out at the warehouse in Capitol Heights on March 31, the deadline. We got 150 entries between 5 p.m. and midnight. With five minutes to go, there was one woman who had her design laid out in the parking lot, filling in the return address."

The memorial is the brainchild of a Vietnam veteran named Jan Scruggs. At the prize announcement, he said: "In 1970 I was a teen-ager with an Army infantry company. By the end of my tour, half my company had been killed or wounded. In 1976 I presented testimony to Congress about the Vietnam veterans -- their lowered self-esteem, marital difficulties and other problems. In 1979 I had the idea for the memorial, for something the government couldn't adequately provide -- recognition. It's not a memorial to honor the war but the sacrifice of the Vietnam veterans."

Scruggs went to Sen. Charles Mathias (R-Md.), who introduced a bill to give the memorial a site. Sen. John Warner (R-Va.) helped raise seed money for a national fund-raising campaign by holding a fund-raising breakfast at his home.

So far, the fund has raised $1.2 million and has set Veterans Day (Nov. 11) 1982 as the date they hope to unveil the memorial, which will be in the Constitution Gardens section of the Mall, near the Lincoln Memorial.

The second-place winner, awarded $10,000 was a team headed by architect Marvin Krosinsky, of Island Park, N.Y., and the third prize of $5,000 was won by an Alexandria team headed by landscape architect Joseph E. Brown. All of the entries will be on display on May 9 at Hangar No. 3 at Andrews Air Force Base.