Rep. Richard Bolling (Do-Mo.) chairman of the House Rules Committee, has entered Bethesda Naval Hospital voluntarily for treatment of an alcohol problem, his office announced yesterday.

Bolling, 63, entered the hospital last week and is in the same kind of alcohol treatment program that President Carter's brother, Billy Carter, former First Lady Betty Ford and Sen. Herman E. Talmadge (D-Ga.) underwent at the Navy's Long Beach, Calif., hospital. He is expected to be released and return to work in about five weeks.

Friends say Boiling's problem with alcohol surfaced only in the last few months, and they blamed it on a series of setbacks in the last few years.

In 1976 Bolling lost a closely contested race for the majority leadership. Nine months later he suffered a heart attack. Last August, his wife, Jim Grant Bolling, who had masterminded the majority leader race and acted as a political sounding board for him, died suddenly of a heart attack at the age of 50. About two months later his aged mother died. Recently an old back injury flared up.

Friends said Bolling began drinking on weekends at his Eastern Shore home. Most of the House staff and members were unaware of the problem. "I didn't even know he drank," one leadership staff member said. "He's always been bright, hard-working as hell and dedicated and I didn't notice any change. If he needs help, maybe I need it, too."

Rep. Gillis Long (D-La.), Bolling's closest friend in the House, said yesterday: "Bolling has a unique ability to look at a problem and take a long-range approach. He wants to solve the problem before it gets serious.

"I visited him and he's in first-class condition. I admire his courage in dealing with the problem in his usual straightforward manner."

After 30 years in Congress, Bolling became chairman of the Rules Committee in January.A highly respected, tough-minded liberal, Bolling frequently led fights for the leadership on the House floor. He already had succeeded in turning the once-balky committee into one that cooperated with the Democratic leadership.

Friends say Bolling had a drinking problem once before, in the early '60s after the death of his mentor, Speaker Sam Rayburn. In that period, Bolling also lost his first attempt to become majority leader and went through a traumatic divorce. From that time until recently, friends said, he had been "on the wagon." In May, Bolling was married for the third time, to Dr. Prudence Orr of Memphis. CAPTION: Bolling in Rules hearing: Friends "didn't notice any change" lately. By James K.W. Atherton - The Washington Post