To visually check out the semiconductor laser emitting, especially in judging Fabry-Perot (F-P) equivalent cavity faces near field luminescence condition and distant field giving out light condition, a test device is designed. By applying the simple component and principle, this device can realize the observation to glowing faculae of semiconductor laser, thus knowing the laser's properties such as optical density distribution, half power angle, angle of divergence, also discovering the concave wiring, the dark spot by observing the Fabry-Perot (F-P) equivalent cavity faces near field luminescence condition and distant field giving out light condition. It is a kind of good method for analyzing the situation of the active area cavity faces cauterization damage and internal structure flaws. So this device is suitable for teaching demonstration and direct observation of laser quality in manufacturing. It is also suitable for array laser chip testing, such as to see if chip gives out light, and to see the glowing intensity directly.