The embodiment of the application discloses a signal processing circuit and a photoelectric detection system including the signal processing circuit. The signal processing circuit comprises a first-grade operational amplifier, a passive device and a first filtering device, wherein the first-grade operational amplifier is configured for superposing the amplitude value of an electric signal output by the photoelectric detector array, and at least one first operational amplifier corresponding to at least one group of photoelectric detectors in the photoelectric detector array; each group of photoelectric detectors in the photoelectric detector array is coupled to the same input end of the first operational amplifier; and the first filtering device is connected with an output end of the first-grade operational amplifier in order to filter the electric signal output by the first-grade operational amplifier, and comprises a diode or a filtering circuit consisting of a resistor and a capacitor. Through the technical scheme provided by the embodiment of the application, the amplitude of the electric signal can be increased; the noise of the electric signal is lowered; and the recovery timeof the electric signal can be improved.