The nation's oldest black business organization, hurled into turmoil after the death last month of its long-time president Dr. Berkley G. Burrell, is facing another, different commotion here.

At least two of its members, both prominent black Washington businessmen, are vying for the presidency of the National Business League -- long considered the voice of small minority businesses.

The league is conducting its 79th annual convention to inform minority firms of business opportunities, to comment on Carter administration policies, to elect one-third of its board of directors and a president to fill the two years of Burrell's unexpired term. Burrell had been president since 1962.

So far, James L. Denson, president of the D.C. Chamber of Commerce, and Theodore Hagans, a Washington developer, have made public their intentions to run for the slot.

Burrell's widow, A. Pat Burrell, who delivered the president's opening address tonight, also was discussed as a possible condidate. In her address, Mrs. Burrell noted the contributions of her husband to minority business and said that the organization will continue to represent "the little people." She also criticized detractors of her late husband and the league.

The league, founded by Booker T. Washington in 1900, is often called upon by the government and large private groups to speak for the black business community, although validity of that position as minority megaphone has been questioned lately. In recent years, Burrell had been criticized within the league for his conservative leadership.

For example, critics point to Burrell's opposition to a Commerce Department plan intended to bring black business into the corporate mainstream by emphasizing the creation of medium and large minority firms rather than concentrating all of its efforts on small, mom-and-pop businesses.

Burrell claimed the plan wouldn't receive "the popular support" of minority enterprises or trade associations because it would exclude almost all minority businesses which are small. Many younger black business leaders, however, hailed the Commerce Department's efforts as progressive.

While criticizing the Commerce plan, Mrs. Burrell said the organization favors the development of medium-sized firms, but not "to the detriment of other minority enterprises in this country."