关键词: 有限自动机, 可识别语言, 邻接矩阵

Abstract: This paper studies the cardinal problem of regular language of finite automata by using adjacency matrix of directed graphs. By establishing a one-to-one correspondence relationship between the regular language of the finite automaton and its directed graph from the initial node（the initial state of the finite automaton） to the termination node（the end state of the finite automaton）, using the adjacency matrix, the cardinality formula of the regular language of the finite automaton is given, and the sufficient conditions for the two automata to be unequal are studied.

Key words: finite automata, regular language, adjacency matrix