Flaxie M. Pinkett, prominent businesswoman, political and community leader, has resigned as president-elect of the Greater Washington Board of Trade, a position that had put her in line to become the first woman and the first black to head the area's largest and most influential business organization.

Pinkett, who plans to retire soon as chairman and president of John R. Pinkett Inc., a leading Washington real estate and insurance firm, said she would not be able to meet the demands the presidency would place upon her.

The surprise announcement of her decision to resign was made in a statement to the board of trade's executive committee Monday.

Pinkett will continue as a director of the board, which elected John T. Hazel Jr. to replace her as president-elect. Hazel is a partner in the law firm of Hazel, Beckhorn & Hanes.

Attempts to reach Pinkett were unsuccessful. She explained in her statement to the executive committee, however, that after 50 years in the firm founded by her father, "the time has come to prepare for retirement. To make this transition will require virtually all of my time and attention during the months ahead."

Pinkett added that other demands would prevent her from devoting the leadership necessary to implement the board of trade's ambitious five-year plan for growth and community involvement.

Pinkett was one of the first women to be accepted for membership in the 90-year-old, formerly all-white male board of trade. For more than 22 years she was an active and influential member and was elected a director in 1974.

The board recognized her contributions to business and community life in the District with the presentation of its prestigious "Man of the Years" award in 1981.

"Flaxie has been an invaluable asset for the board of trade," Thomas J. Owen, the board's president, said yesterday. Owen, who would have been succeeded by Pinkett as president next year, said her decision came as a surprise and disappointment to members of the board. But, he added, "everybody respects her decision."

Louise Lynch, one of nine women directors of the board of trade, called Pinkett's withdrawal "a real loss," and added: "She has made fantastic contributions to the board and the Washington community as a whole."