Abstract: Method and device for light signal reception. This device can selectively execute a comparison mode or a gain mode. In the device, a transmitter transmits a light beam to a target. A receiver receives the light beam reflected from the target and outputs a corresponding received signal. In the comparison mode, it is determined whether a pulse in the received signal is higher than a reference voltage level. When the pulse is higher the reference voltage level, the pulse is outputted. The gain mode is executed and the received signal is amplified and output when no pulse is higher than the reference voltage level in the received signal. The method and device of the present invention can be applied to range finders, the comparison mode is executed during short-distance measurement and the gain mode is executed during long-distance measurement thereby measuring the target distance from several meters to a thousand meters.