Howard Mehring, 47, one of the most important of the Washington color painters, died yesterday morning after a heart attack at Anne Arundel General Hospital in Annapolis, where he had been a patient for the past week.

His career, though brief, was brilliant. Between 1957 and 1968 - when he mysteriously ceased painting - Mr. Mehring made a serie of striking, airy pictures, the best of which must rank with the most innovative abstract paintings of that time.

Fifty of his finest works were assembled here three months ago for a major retrospective show at the Corcoran Gallery of Art. That exhibition proved that Mr. Mehring's early pictures are of pivotal significance. In them one can trace the historical transition between the rather cramped and tortured paintings of the New York School and the cooler, and more colorful, art that was to come.

By abandoning the anguish of New York action Painting, and instead, delighting in pure and open color, the Washington color painters changed the look of abstract art. Though Howard Mehring's pictures from the 1950s are not as famous or as costly as those by his older colleagues, Morris Louis and Kenneth Noland, it is in Mr. Mehring's paintings that the move to the new style is most clearly seen.

Though it is sure that he was influenced by the dripped canvases of Jackson Pollack, Mr. Mehring found a way of opening the field through hue instead of line. But as he kept on painting, and began to use hard edges, that lovely, airy openness began to lock, to close. Though they retained a mood of urgency, of passion, his works grew ever stricter until, in 1968, the artist ceased to paint.

Mr. Mehring, it was clear, had not lost his love of painting. He visited the National Gallery of Art almost every day. He loved to discuss painting. When asked why he had stopped, he grew evasive. Some of his admirers felt he'd lost his nerve.

It is an irony of art histroy that now that Mr. Mehring is dead, his abandonment of painting seems suddenly correct.

"Some artists," said Corcoran curator, Jane Livingston, who organized last December's retrospective, "blossom when they're young, and then repeat themselves until they grow stale. Mehring was not one of them. His art developed freely. He had the insight - or the guts - to stop at the right point. He was among the handful of guiding, revolutionary painters of its time. His contribution stands."

Artist Gene Davis yesterday called Mr. Mehring "one of the premier painters of the so-called Washington [WORD ILLEGIBLE] school. While our contact had being minimal in recent years, I looked long and hard at his early work - and learned from it. In many ways he was the most lyrical of us all."

Howard Mehring was born in Washington in 1931. He attended McKinley Hich School (as did the color painters Gene Davis and Paul Reed). He then entered Wilson Teachers College here. In 1953, he graduated first in his class.

That year, aged 21, Mr. Mehring worked as a student Berkowitz. It was through Berkowitz's Washington workshop Center that Mr. Mehring met many of the early members of the Washington color school. He entered Catholic University, where he studied design with Noland and became a friend of the painter Thomas Downing, with whom he later shared a studio.

In 1955, there were only three abstractiins - one each by Noland, Downing and Mr. Mehring - accepted by the jury for the Corcoran Area Show. The painter Andrew Wyeth as a member of the exhibition jury, and he picked all three.

Mr. Mehring shared with Noland a continuing interest in Reichian therapy and in progressive jazz. When he discussed his masters, Mr. Mehring often mentioned not only Pollock and Vermeer, but Lenny Tristano, Charlie Parker and Thleonious Monk.

His first commericial show here was a "New Faces in Washington" exhibition mounted by Franz Baders' Gallery in 1955. Mr. Mehring later showed with the Origo, Jefferson Place, and Pyramid galleries here.

As the international art world began to take notice of the Washington color painters, his career seemed to flourish. Such collectors as Harry Abrams, the publisher of art books, and such curators as Alfred Barr, of the Museum of Modern Art, and Walter Hopps, then of the Pasadena Museum, purchased pictures from the Mehring show that opened in New York at the A.M. Sachs Gallery in 1966.

"I am using the same basic composition over and over again," said Mr. Mehring in 1962. "I never seem to exhaust its possibilities . . . Conceptually I am often way ahead of where I am painting, but I discipline myself to stay with each series until I am sure I am through."

Though in the last years of his life he returned to drawing, it appears that in 1968 he decided he as finished.

"Not so long ago," F. A. Carmean, curator of 20th century art at the National Gallery, "Howard brought me a sketchbook of his drawings. I'll never forget that day. Some people say his nerve had failed. I don't think so. There was no trace of uncertainty or insecurity in those drawings. The sketchbook started on page one, and just went on from there. His career was tragic. He died too young."

A room of Mr. Mehring's paintings from 1969 to 1962, borrowed from collector Vincent Melzac, is currently on view at the Phillips Collection here.

Mehring, who maintained no permanent residence - he most recently was living in a Maryland motel - was visiting friends when he became ill last Thursday and was taken to the hospital in Annapolis. On Thursday, he suffered a heart attack. Yesterday morning a second attack proved fatal. He is survived by his mother, Florence, a brother, Warren Chaires, both of Woodstock, Va., and a niece, Karen Corey, of Waldorf, Md.