Education Secretary William J. Bennett's report that American education is doing better but not well enough met Monday with a failing grade from one teachers union for absolving the federal government "from any responsibility for improving public education."

Teachers deserve the credit for the academic progress in the five years since a similar study became a biting critique of U.S. education called "A Nation At Risk," said Mary Hatwood Futrell, president of the National Education Association.Another teachers union called the Bennett report "a mixed bag."

His report, a follow-up requested by President Reagan for the fifth anniversary of "A Nation At Risk," said that American schools "have begun the long climb back" but that the nation is still at risk from an academic system rife with mediocrity and resistant to change.

Bennett says American teenagers are taking more math, science and advanced placement courses and scoring somewhat higher on college-entrance and other tests.

But "curricular foolishness has not been eliminated from American high schools," he said, and the schools "are still much too cavalier about homework."

In his evaluation of the impact of school reform, called "American Education: Making It Work," Bennett said:

"American education has made some undeniable progress in the last few years. The precipitous downward slide of previous decades has been arrested, and we have begun the long climb back to reasonable standards.

"We are doing better than we were in 1983. But we are certainly not doing well enough. We are still at risk."

Bennett will deliver his report to Reagan in a White House ceremony Tuesday, the fifth anniversary of the provocative report by the National Commission on Excellence in Education that warned of "a rising tide of mediocrity" in U.S. schools.

The National Education Association planned to mark the anniversary with a protest in Lafayette Park across from the White House.

"I give the report a failing grade," said Futrell, the NEA president. "It absolves the federal government from any responsibility for improving public education. On the plus side, teachers deserve the credit for the academic progress the students have made since 1983.

"Had it not been for the efforts of Congress, which held back the tide of budget cuts proposed by the Reagan Administration," she said, "schools would have been in much worse shape, which gives Congress an A."

"Its a mixed bag," said Jane Usdan, spokeswoman for the American Federation of Teachers. "He highlights what happened over the last five years, that there's been a lot of good, including increases in teachers' salaries and standards that have been tightened."