A new method to test divergence angle of high-power plane-array lasers is presented. The divergence angle is calculated based on geometry characteristics of two facula curves detected at the different positions to the laser. Facula curves are gained through scanning by two hemicycle probes which have different radius. The testing error induced by looking plane-array laser as point lamp-house is reduced by this method. Further the problem that detector is destroyed or burned because of high power is resolved. The results show this testing system can test the divergence angle of high power plane-array lasers reliably.