The invention relates to the field of CMOS image sensors, and provides a digital pixel sensor which can unify change rates of two sections of reference voltages in the two-section comparing technique. Thus, according to the technical scheme, a digital pixel exposure method using a multi-ramp voltage as a reference voltage is adopted and comprises the following steps that the method is implemented by means of a PWM pixel array, PWM pixels are composed of a PD, a MRST, a pixel-level comparator, a line-level comparator and a pixel-level or line-level or array-level storage, the input end of the pixel-level comparator has a PD node voltage and a set reference voltage, a PWM type digital pixel enters an exposure stage after resetting, and exposure time is divided into a reset sampling stage Trs and an integral sampling stage Tis; the reference voltage of the reset sampling stage linearly rises to Vref_rsh from Vref_rsl. The method is mainly applied to designing and manufacturing of the CMOS image sensors.