To meet the application requirements of large area array CMOS image sensors(CIS), in this paper, a ramp signal generator with slop and samp mode adjustment is presented. And the design ,simulation and layout are implemented, using 90nm(1.2V/2.8V)1P5M CIS process. The design results show that this circuit has simple ctructure,small area, adjustable slope and working mode. The slope amplitude is >0.5V , reset time is<70ns ,DNL is +0.018LSB/-0.012LSB ,INL is+0.78LSB/-0.013LSB , which meets the design and engineering application of large array CIS.