The national flag of Angola came into use at independence on November 11, 1975. It is split horizontally into an upper red half and a lower black half.
Later the explanation was made less party-specific: The red is for the blood spilt by Angolans during their independence struggles, while the black is for the continent of Africa. The symbol in the middle is of a crossed cog wheel (representing workers and industry) and machete (representing the peasantry) with a gold star. It was adopted during a time when Angola had a Marxist government, and thus was supposed to evoke the image of the hammer and sickle found on the flag of the former Soviet Union, a common symbol of Communism. The flag is most recently described and explained in article 162 of the Constitutional Law of the Republic of Angola (Constitution) of August 25, 1992.
As in some other African countries, this flag is a modification of the ruling party’s flag. The guerilla movement and later governing party, the Popular Movement for the Liberation of Angola (MPLA), used the same design with a golden star in the center. Red stood for socialism and black for Africa. The star was modeled after the red star of the Soviet Union, which sponsored the MPLA. Wikipedia