WASHINGTON (AP) _ The faces stare at you in unrelenting succession, none with a smile. They are faces of adults without hope and children without childhood.

There is photograph after photograph of families being evicted, mother and children sitting outdoors on their piled-up belongings. They are pictures that have the impact of war, of the Great Depression, of children orphaned and victimized by fighting not of their making.

These are the scenes in a new exhibit called ''Homeless in America,'' that opened Tuesday at the Corcoran Gallery, a block from the White House. The exhibit of 64 pictures will tour 32 cities in the coming years to act as, in the words of its sponsors, ''a centerpiece for public education.''

''It's a national disgrace that in this country of plenty there are people who don't have a place to live,,'' said Susie Elson, immediate past president of the National Mental Health Association, which joined in producing the exhibit along with Families for the Homeless, a group that includes congressional, administration and media families.

Tipper Gore, wife of the senator from Tennessee, headed the project.

''In America we have become adjusted to the image of poverty,'' she said. ''The half-clothed child in a shack in Appalachia is what many people still think of when they think about poor people in this country,'' she said before the exhibit opened. ''Today's realities far outstrip this outdated image and that is why we felt it was important to have top photojournalists communicate through the power of their images.''

Simultaneously with the opening of the exhibit, a book of the photographs was published. Many of the photographers represented in the exhibit and book were commissioned by Michael Evans, formerly President Reagan's personal photographer.

''The exhibit will endure as a lasting work of art and that, too, is important,'' said Mrs. Gore. ''But the key component, the key element is using the photographs to ... drive home that there are maybe three million homeless people in this country, that they are families, that they are children, the elderly, that they are veterans, that they are mentally ill, that they are the most vulnerable people in our society and that they are growing.''

Evans said the project cost $450,000. Its principal funding was provided by Triangle Industries, Inc.

The photographs, all black and white, depict such urban scenes as a pair of legs sticking from a box that obviously served as a night's accommodations; a child eating from a metal bowl in her home, under an underpass; a small girl weeping as a humane society worker removes her cat in a cage, prior to her own eviction; families with their belongings in plastic bags.

They show two young men scavenging through a metal trash container; a man and woman asleep on a park bench, his knee serving as her pillow; a food line, with the splendor of the Dallas skyline as a backdrop.

The honorary patron of the project is Barbara Bush, wife of the vice president. The board of directors includes Susan Baker, wife of White House chief of staff Howard Baker.