High resolution of surface plasmon resonance (SPR) detection is of vital importance.SPR biosensing system resolution is determined by intrinsic sensitivity of biochip and light signal acquisition system.In this article,different signal acquisition system resolutions on photodetector were analyzed based on light intensity and phase detection.Result shows that charge coupled device (CCD) with larger numbers of pixels is potential to achieve higher detection resolution.A 64 pixel line array CCD and a 12 bit ADC can achieve resolution of 10~(-7) refractive index unit (RIU).In array detection mode,increasing of detection throughput is at the cost of decreasing system resolution.Simulation analysis indicates that,if noise is taken into account,phase modulation methods are capable of providing better noise reduction performance than intensity methods. High resolution of surface plasmon resonance (SPR) detection is of vital importance. SPE biosensing system resolution is determined by intrinsic sensitivity of biochip and light signal acquisition system. This article, different signal acquisition system resolutions on photodetector were analyzed based on light intensity and phase detection. Result shows that charge coupled device (CCD) with larger numbers of pixels is potential to achieve higher detection resolution. A 64 pixel line array CCD and a 12 bit ADC can achieve resolution of 10 -7 RIU) .In array detection mode, increasing of detection cost is at the cost of decreasing system resolution.Simulation analysis indicates that, if noise is taken into account, phase modulation methods are capable of providing better noise reduction performance than intensity methods.