The invention discloses a device for testing an optical sensor used for fires and explosions. The device comprises a control system, a holder system, a control box, a driving circuit, a light source, an optical system, a data acquisition circuit and a counting circuit, wherein the control system is connected with the driving circuit through the control box, spectrum and intensity of the light source are selected through the control box, the driving circuit drives the light source to emit light, the light emitted by the light source is received by a sensor to be tested after being processed by the optical system, the data acquisition circuit receives a response signal of the sensor and sends the response signal to the control system, the counting circuit also acquires the response signal of the sensor, and response time of the senor is measured through the counting circuit; and the holder system is connected with the control system, the sensor to be tested is arranged on the holder system, and the control system controls the holder system to rotate and is used for acquiring angle information of the holder system. The device and the method can accurately test fire major performance parameters of the optical sensor.