KANSAS CITY, Mo. (AP) _ A burglar with an eye for art stole an original watercolor by Thomas Hart Benton valued at $46,000, an autographed color photograph and two other paintings, police said.

The Benton watercolor, ''Trading at Westport Landing,'' apparently was a detailed study for Benton's mural ''Old Kansas City,'' commissioned by the River Club and completed in 1956.

The most recent appraisal of the study put its value at $46,000.

Also stolen in Monday's break-in was a color photograph of ''Persephone,'' signed by the artist. ''Persephone'' is a 1939 Benton painting bought by the Nelson Gallery last year for a reported $2.5 million.

A painting of streetcar tracks by Duard Marshall and a work depicting a cherry tree by an artist identified only as Winchell, also were taken, but nothing else in the house was touched.

Sgt. Bob Watts, of the Metro Patrol burglary unit, said the fact that only the paintings and photo were stolen during the break-in ''seems to indicate they went there for the specific purpose of stealing his art.''

The owner, who asked not to be identified, and his family were friendly with Benton and the owner's father bought the Westport landing painting and bequeathed it to his son.