The University of the District of Columbia has suspended 880 students and placed an additional 1,800 on probation as a first step in a far-reaching effort to improve the school's academic standards, university officials said yesterday.

The action marked the first time the university has enforced a policy, which the UDC board of trustees originally adopted in 1979, requiring the school to place on academic probation those students who have lower than a 2.0 cumulative average and to suspend those who fail to achieve a 2.0 average after completing three semesters or 30 credit hours at the university.

The suspended students will be barred from enrolling in any courses at UDC for one semester. The students on probation will have to take a reduced course load, thus slowing their progress toward graduation, and will be suspended if they do not improve their grades over the next three semesters.

Although the stiffer standards went into effect before his arrival at the 14,000-student university, UDC's new president, Benjamin H. Alexander, said the policy will be strictly enforced during his administration.

UDC, which has an open admissions policy and draws most of its students from the problem-plagued D.C. public schools, has been criticized in the past as being lax in its academic standards.

"Enrolling at UDC is a right," Alexander said, referring to the school's open admissions policy. "But graduating from UDC is going to be a privilege . . . Students will not be able to sit in class for long periods of time without reaching an adequate level of achievement."

Dionne Porter, president of UDC's undergraduate Student Government Association, said many students probably will protest the strict enforcement of the suspension policy, but added that Alexander "is only doing something which should have been done all along."

School officials said the policy had not previously been enforced because the university did not have a computerized system for centralizing all student transcripts until two years ago.

Alexander said, "I have been informed that this policy was not enforced because some people were afraid of the heat."

Alexander, who has been on the job since Aug. 1, also announced yesterday planned changes he said he intends to present to the board of trustees for approval.

Over the next three years, he said, he wants the university to establish doctoral programs in each of its five academic colleges; expand course requirements in foreign languages; initiate an effort to increase the enrollment of white, Asian and Hispanic students at the predominantly black school; and secure funds for the construction of a downtown campus at Mount Vernon Square.

Alexander said he also is considering requiring students to pass a reading test in addition to the current math and English composition tests students must pass before graduation.

The proposed doctoral programs, Alexander said, "will take UDC from second-class status to first-class status" as a university. The school currently offers only bachelor's and master's degrees.

He said he wants the current requirement of one year of a foreign language for students enrolled in a four-year program to be expanded to two years or more, so that more students might be encouraged to enter the field of international relations. He said his staff also will work to establish more exchange programs with foreign universities.

Alexander said he plans to take his drive to recruit whites, Asians and Hispanics directly to the neighborhoods where these groups live. UDC's enrollment is about 85 percent black, 3 percent white, 5 percent Asian and one percent American Indian, according to the school's 1980 annual report, with the race of the remaining students not recorded. Less than one percent of the students on record have Hispanic surnames.

The new president said he plans to win funds for the construction of a Mount Vernon campusa project -- which has been stalled for the past five years -- through a strong public relations campaign both in Congress, whose control over the D.C. government's purse strings extends to UDC, and among business leaders.

Alexander, who launched unorthodox publicity drives in his previous post as president of Chicago State University, said he plans to court the support of the various congressmen who serve on the District appropriations subcomittees by inviting them to VIP lunches at the university and sending them birthday cards.

He also said he has coined a slogan to attract more honors students to the school: "UDC is the best bargain in education in town."