The existence of gravitational wave is the greatest predictions of Einstein’s theory of general relativity. The detection of gravitational wave is one of the important frontier sciences of physics. The gravitational wave astronomy based on the detection of gravitational wave is a new interdisciplinary science. It is a big complimentary and expanding of traditional electro-magnetic astronomy. As a high precision optical instrument and the key equipment of gravitational wave astronomy,laser interferometer gravitational detectors are developing very quickly in the world. It opened a new era of gravitational wave detection. The basic optical structure of laser interferometer gravitational detector and its main parameters have been discussed. The characteristics of mirrors and the measurement method for their parameters have been introduced.