An image sensing system, comprising: a light emitting module, configured to emit an incident light according to a modulation signal; and a pixel array, configured to receive a reflected light corresponding to the incident light, wherein the pixel array comprises a plurality of pixel units, each pixel unit comprises a pixel light sensing region and a pixel circuit, the pixel circuit is coupled to a first collection node (FD_A') and a second collection node (FD_B'), characterized in that, the pixel circuit comprises: a first alternative charging module (42_A), comprising: a first capacitor (C_A), with a first terminal (D A ') and a second terminal (N A '); a first shutter switch, coupled between the first terminal (D A ') and the first collection node (FD_A'); a second shutter switch, coupled between the second terminal (N A ') and the first collection node (FD_A'); a third shutter switch, with a terminal coupled to the second terminal (N A '), and another terminal receiving a voltage (VCCR); and a fourth shutter switch, with a terminal coupled to the first terminal (D A '), and another terminal receiving the voltage (VCCR); and a second alternative charging module (42_B), comprising: a second capacitor (C_B'), with a third terminal (D B ') and a fourth terminal (N B '); a fifth shutter switch, coupled between the third terminal (D B ') and the second collection node (FD B'); a sixth shutter switch, coupled between the fourth terminal (N B ') and the second collection node (FD_B'); a seventh shutter switch, with a terminal coupled to the fourth terminal (N B '), and another terminal receiving the voltage (VCCR); and an eighth shutter switch, with a terminal coupled to the third terminal (D B '), and another terminal receiving the voltage (VCCR). a light emitting module, configured to emit an incident light according to a modulation signal; and a pixel array, configured to receive a reflected light corresponding to the incident light, wherein the pixel array comprises a plurality of pixel units, each pixel unit comprises a pixel light sensing region and a pixel circuit, the pixel circuit is coupled to a first collection node (FD_A') and a second collection node (FD_B'), characterized in that, the pixel circuit comprises: a first alternative charging module (42_A), comprising: a first capacitor (C_A), with a first terminal (D A ') and a second terminal (N A '); a first shutter switch, coupled between the first terminal (D A ') and the first collection node (FD_A'); a second shutter switch, coupled between the second terminal (N A ') and the first collection node (FD_A'); a third shutter switch, with a terminal coupled to the second terminal (N A '), and another terminal receiving a voltage (VCCR); and a fourth shutter switch, with a terminal coupled to the first terminal (D A '), and another terminal receiving the voltage (VCCR); and a first capacitor (C_A), with a first terminal (D A ') and a second terminal (N A '); a first shutter switch, coupled between the first terminal (D A ') and the first collection node (FD_A'); a second shutter switch, coupled between the second terminal (N A ') and the first collection node (FD_A'); a third shutter switch, with a terminal coupled to the second terminal (N A '), and another terminal receiving a voltage (VCCR); and a fourth shutter switch, with a terminal coupled to the first terminal (D A '), and another terminal receiving the voltage (VCCR); and a second alternative charging module (42_B), comprising: a second capacitor (C_B'), with a third terminal (D B ') and a fourth terminal (N B '); a fifth shutter switch, coupled between the third terminal (D B ') and the second collection node (FD B'); a sixth shutter switch, coupled between the fourth terminal (N B ') and the second collection node (FD_B'); a seventh shutter switch, with a terminal coupled to the fourth terminal (N B '), and another terminal receiving the voltage (VCCR); and an eighth shutter switch, with a terminal coupled to the third terminal (D B '), and another terminal receiving the voltage (VCCR). a second capacitor (C_B'), with a third terminal (D B ') and a fourth terminal (N B '); a fifth shutter switch, coupled between the third terminal (D B ') and the second collection node (FD B'); a sixth shutter switch, coupled between the fourth terminal (N B ') and the second collection node (FD_B'); a seventh shutter switch, with a terminal coupled to the fourth terminal (N B '), and another terminal receiving the voltage (VCCR); and an eighth shutter switch, with a terminal coupled to the third terminal (D B '), and another terminal receiving the voltage (VCCR).