Sen. Hubert H. Humphrey (D-Minn.), whose cancerous bladder was removed last October, is scheduled to be operated on today for an intestinal blockage, doctors in Minneapolis announced yesterday.

Humphrey, 66, a former vice president and the Democratic presidential candidate in 1968, was admitted to the hospital Tuesday afternoon suffering from "intestinal problems."

The University of Minnesota Hospitals reported later that Xrays and test showed that Humphrey has a partial blockage of his intestine that was causing him "some discomfort."

Cancer specialists not connected with Humphrey's case called an intestinal blokage "a well-recognized complication" of an operation in which a bladder was removed because of cancer. Humphrey would be a prime candidate for that type of complication, one expert said, because doctors removed a six-inch section of his small intestine to use as a drain for urine.

Nonethless, cancer specialists acknowledged that what appears to be a blockage could be symptoms of Humphrys's cancer.

Humphrey has been spending the Senate's summer recess at his home in Waverly, Minn., when he was taken to the hospital.

He was examined there by Dr. John K. Najarian, head of the department of surgery, who is not a cancer specialist but is best know for his success in kidney transplants, and Dr. B. J. Kennedy, a cancer specialist who is not a surgeon.

As far as could be determined, none of the bladder cancer specialists who operated on Humphrey last October at New York's Memorial-Sloan Kettering Cancer Center will bw in Minneapolis for today's surgery.

Vice President Mondale, who was in Minneapolis last night for a political rally, reported after a 20-minute visit with Humphrey. "He is in excellent spirits. He looks good. We had a long reflective discussion."