Use of Laser weapon in battle field has made StaR-borne laser warning equipment as necessity. Traditional Laser warning system has single function. Using quadrant detector as probability warning system, inducts the IRFPA for accurate orientation detection, constitutes a new style laser warning system. The system has performance of multi-band, high detecting threshold, wild-field and high angle precision. The design of laser warning system is expounded in detail, experiment result is analyzed, and some improving suggestion is given.