The invention provides a positioning system and method of a spacecraft subjected to space junk collision. The positioning system comprises in-plane shearing wave piezoelectric sensors (1), a data transmission line (2), a charge amplifier (3) and a data processing unit (4), wherein the in-plane shearing wave piezoelectric sensors (1) are glued and fixed on an inner surface of a spacecraft structure (5); a sensor array is composed of the plurality of in-plane shearing wave piezoelectric sensors (1) and the in-plane shearing wave piezoelectric sensors (1) are connected with the charge amplifier (3) through the data transmission line (2); and the charge amplifier (3) is connected with the data processing unit (4) through the data transmission line (2). After collision occurs, the data processing unit (4) is used for acquiring data of the in-plane shearing wave piezoelectric sensors (1) in real time, and the positioning system is used for carrying out collision positioning of space junks through in-plane shearing wave SHO (Super High Output) wave and a four-point geometric positioning method, so that high-precision positioning of a collision position can be realized.