Abstract: Using the data of Crustal Movement Network of China, the authors studied the characteristics of base line length and direction before and after Kunlun Mountain earthquake. According to the ruptured direction of Kunlun Mountain earthquake, the authors discussed the base line change characteristic difference in the different bearing, and theoretically discussed the sensibility problem that change of length and direction of base line to the earthquake. The study shows that, ① when base line direction and earthquake fracture direction tend to be consistent, the sensibility of base line length is higher than base line direction; ② when the base line direction and earthquake fracture direction tend to be vertical, the sensibility of base line direction is higher than base line length; ③ when the base line direction and earthquake direction tend to be an angle with 45° or so, the base line length and direction show a certain influence on the earthquake, at the same time, probably appear obvious changes before the earthquake.

Key words: Kunlun Mountain earthquake with M_S8.1, Direction of baseline, Length of baseline, Crustal movement