An image sensor, comprising: a pixel circuit array, wherein each pixel circuit is configured to generate an output signal according to a received light signal; and an output circuit, comprising an operational amplifier, wherein the operational amplifier comprises a first input end and a second input end, first output ends of a plurality of pixel circuits of the pixel circuit array are connected to the first input end of the operational amplifier, and second output ends of the plurality of pixel circuits are connected to the second input end of the operational amplifier; wherein the operational amplifier is configured to simultaneously receive output signals of a plurality of pixel circuits in the pixel circuit array, and output a signal average value of the output signals of the plurality of pixel circuits, so that the output signals of the plurality of pixel circuits completes combination and averaging within the output circuit; wherein the operational amplifier further comprises a plurality of groups of transistors connected to its output end, wherein each group of transistors comprises a first transistor and a second transistor connected in series, the number of the plurality of groups of transistors is the same as the number of the plurality of pixel circuits, a transconductance of the first transistor is the same as that of a source follow input transistor of a pixel circuit, the second transistor is a gating switch transistor same as a gating switch transistor of the pixel circuit, and the source follow input transistor and the gating switch transistor are connected in series between the first output end and the second output end of the pixel circuit; the pixel circuit further comprises a photodiode, a parasitic capacitor, a reset switch transistor and a transmission transistor, and an cathode of the photodiode is grounded, an anode of the photodiode is connected to a source of the transmission transistor, a gate of the transmission transistor is controlled by a transmission signal, and a drain of the transmission transistor is connected to one end of the parasitic capacitor, a gate of the source follow input transistor and a source of the reset switch transistor, the other end of the parasitic capacitor is grounded, a drain of the reset switch transistor is connected to a reset voltage, a gate of the reset switch transistor is controlled by a reset signal, a gate of the gating switch transistor is controlled by a gating signal, a source of the source follow input transistor is connected to a drain of the gating switch transistor, and one end of a drain of the source follow input transistor and one end of a source of the gating switch transistor are used as the first output end and the second output end of the pixel circuit, respectively. a pixel circuit array, wherein each pixel circuit is configured to generate an output signal according to a received light signal; and an output circuit, comprising an operational amplifier, wherein the operational amplifier comprises a first input end and a second input end, first output ends of a plurality of pixel circuits of the pixel circuit array are connected to the first input end of the operational amplifier, and second output ends of the plurality of pixel circuits are connected to the second input end of the operational amplifier; wherein the operational amplifier is configured to simultaneously receive output signals of a plurality of pixel circuits in the pixel circuit array, and output a signal average value of the output signals of the plurality of pixel circuits, so that the output signals of the plurality of pixel circuits completes combination and averaging within the output circuit; wherein the operational amplifier further comprises a plurality of groups of transistors connected to its output end, wherein each group of transistors comprises a first transistor and a second transistor connected in series, the number of the plurality of groups of transistors is the same as the number of the plurality of pixel circuits, a transconductance of the first transistor is the same as that of a source follow input transistor of a pixel circuit, the second transistor is a gating switch transistor same as a gating switch transistor of the pixel circuit, and the source follow input transistor and the gating switch transistor are connected in series between the first output end and the second output end of the pixel circuit; the pixel circuit further comprises a photodiode, a parasitic capacitor, a reset switch transistor and a transmission transistor, and an cathode of the photodiode is grounded, an anode of the photodiode is connected to a source of the transmission transistor, a gate of the transmission transistor is controlled by a transmission signal, and a drain of the transmission transistor is connected to one end of the parasitic capacitor, a gate of the source follow input transistor and a source of the reset switch transistor, the other end of the parasitic capacitor is grounded, a drain of the reset switch transistor is connected to a reset voltage, a gate of the reset switch transistor is controlled by a reset signal, a gate of the gating switch transistor is controlled by a gating signal, a source of the source follow input transistor is connected to a drain of the gating switch transistor, and one end of a drain of the source follow input transistor and one end of a source of the gating switch transistor are used as the first output end and the second output end of the pixel circuit, respectively.