Barbara Hackman Franklin, the feisty and outspoken lone Republican on the Consumer Product Safety Commission, is resigning her position.

One of the charter members of the commission, which began operations in May 1973, Franklin said last night that she would be sending her letter of resignation to President Carter today, but added that it would not become effective until next Feb.1.

"I'm announcing it now to allow ample apportunity for the administration to name and confirm a successor," Franklin said in an interview. Her term would have expired in October 1979.

Franklin, 38, came to Washington in April, 1971, to work in the White House as a presidential assistant with the task of recruiting women for top government policymaking jobs.

A former assistant vice president of Citibank in New York City, and one of the first women to graduate with a master's degree from the Harvard Business School, Franklin was a significant factor in the tripling of the number of women in key government executive positions during her stay in the White House.

In May 1973, she was tapped to be one of five new commissioners at the CPSC, an independent regulatory agency founded by Congress to protect the public from unreasonable risks of injury or illness caused by consumer products.

"I've been here from the beginning," she said, "and I think it has reached a point when it is time for me to move on. And I need a vacation."

The beleagured agency was given its first Democratic chairman two months ago when Susan King was named to head it. King, Franklin and Democrat Edith Barksdale Sloan have given the agency a female majority - one which Franklin hates to jeopardize by leaving.

"The irony is that when I was in the White House recruiting women, and the law creating the CPSC passed Congress, I hoped right away that we could make it the first federal agency with a majority of women on it," she said.

Though a Republican, and a Nixon appointee, Franklin is considered an independent voice on the commission, frequently siding with Democratic members.

Well liked by commission staffers, she has certain favorite projects, including at least one she plans to mention in her letter of resignation.

"I am going to urge the president to exert more leadership in the area of achieving a national cancer policy," she said last night. "Things have been moving," but not as fast as I would like and not from the top as much."

Franklin was instrumental in getting the White House to take a serious look at the cancer problem through an interagency task force.