A light sensing method applied to a light sensing system comprising a first light sensor and at least one light source. The first light sensor comprises a plurality of light sensing units. The light sensing method comprises: (a) respectively controlling an exposure condition for each of the light sensing units according distances between each one of the light sensing units and the light source； and (b) controlling the light sensing units to sense the light from the light source according to the exposure condition. The light sensing system can have a better SNR via adjusting the exposure condition for each one of the light sensing units. Such light sensing method can be applied to compute physiological parameters.
