Montgomery County school officials, calling for a profound shift in a two-year-old Board of Education policy on integration, yesterday proposed lowering the threshold at which the board may act to correct a school's "racial imbalance."

In a five-page policy statement on "quality integrated education," a committee of ranking school officials called for changes in the formula that determines when the board may take steps, including busing, to increase the number of integrated classrooms in the county.

Under a formula tied to the systemwide minority enrollment of 25.4 percent, the board may now order actions such as busing or curriculum changes when an individual school's minority population exceeds 64.1 percent. If the integration policy proposed yesterday is approved by the seven-member board, those same steps could be ordered if a school's minority population exceeds 45.4 percent.

The proposed formula represents a "subtle but rather profound change" in school board policy, said Steve Derby, a member of the committee that drafted the plan and the board's lawyer on desegregation matters. Derby said the proposal would promote the goal of combining quality education and racial integration in the public schools.

"This would stop racial isolation," Derby declared.

Officials said they are uncertain when the board may vote on the new policy. But even as a topic of debate, the proposal marks a dramatic shift from the school board of 1981, which altered a 1976 racial balance policy to include the 64.1 percent rule.

The majority that approved that standard was turned out of office in last November's elections.

The hour-long debate on the integration proposal yesterday came just five hours after the board, citing racial balance goals, voted to deny 11 parents' requests that their children be allowed to transfer from schools with high minority enrollments. Several of the requests were from parents whose children attend East Silver Spring Elementary, which is roughly 50 percent minority, officials said.

Board President Blair G. Ewing said the requests would disrupt the board's integration goals.

Board members Suzanne K. Peyser and Marian L. Greenblatt voted to approve many of the transfers, saying they would not disrput the policy.

"Racial isolation . . . is poor education," said Ewing. "One case does not allow that to occur," he added, in an apparent reference to a single East Silver Spring transfer request the board granted last week. However, "a series of cases" could lead to a disproportionate minority population in some schools, he said.

There are currently 13 Montgomery schools with more than 50.8 percent minority enrollment, or twice the countywide average. With the minority enrollment growing at a rate of roughly 2 percent each year, planners expect minorites to make up more than half the enrollment in some sections of southern Montgomery within the next five yuears.

The proposed integration policy would establish an array of steps the board could take to achieve racial balance. Long-distance busing of students solely to achieve a numerical balance should be avoided, the statement said.

In other action yesterday, the board indefinitely postponed debate on proposals by Greenblatt and Peyser to stiffen high school graduation requirements.