Pixel unit, global exposure reading method thereof and global exposure image sensor

The invention provides a pixel unit, a global exposure read-out method thereof and a global exposure image sensor, and the global exposure read-out method comprises the steps: carrying out the state reset and charge zero clearing of corresponding devices and nodes of a voltage domain pixel circuit in a pixel reset time period, and carrying out the state reset and charge zero clearing of corresponding devices and nodes of a voltage domain pixel circuit in an exposure and storage time period. Controlling the voltage domain pixel circuit to be switched to a reset storage state and store a reset signal, then controlling the voltage domain pixel circuit to be switched to an exposure storage state, storing a pixel signal generated by the quantum dot pixel in global exposure work by the voltage domain pixel circuit, and in a quantization time period, outputting the pixel signal in the quantization time period. The effective value of the image signal is determined based on the reset signal and the pixel signal read b