William J. Small, forced out of the presidency of NBC News in February, was named president and chief operating officer of United Press International today.

Small, 55, succeeds Roderick W. Beaton, who retired on Sept. 1 as head of UPI.

An often abrasive and brusque personality, Small becomes the first president of the 75-year-old news agency under its new owners. On June 2, Media News Corp. acquired the financially troubled wire service from E.W. Scripps Co.

Small was meeting with UPI management today and was not available for comment.

In a prepared statement, he said, "My colleagues and I are eager to continue to improve the service to the point that no newspaper will want to be without it."

Small, who joined CBS News in 1962, was Washington bureau chief for the network for 12 years.

In 1979, after being passed over for the presidency of CBS News, he became head of NBC News. Long-time NBC News figures, including commentator David Brinkley, were upset because Small brought a number of correspondents from competitor CBS with him when he made the move. Brinkley soon after moved to ABC News.

Apparently, the new owners of UPI hope that Small's reputation and administrative talents will help the image of the struggling news agency, which was for sale for two years before newly formed Media News acquired it..

UPI lost $4 million in 1981. But a spokesman for the news agency says it hopes to cut that by more than $1 million this year. The wire service has 7,000 subscribers, including 1,800 newspapers and 4,000 radio and television stations.