In photon correlation spectroscopy particle sizing techniques, only when the setting of the dynamic range of photon correlator matches the decay range of target scattered light intensity autocorrelation function can the autocorrelation function produced by the photon correlator reach optimum resolution. In practice, parameter modification is indispensable in repetitive measurements. To solve the problem, an adaptive adjust method for dynamic range of photon correlator was presented in this paper. Through the selection of original sample time and redistribution of correlator channel sample times, photon correlator dynamic range can be adaptively adjusted to match the decay range of autocorrelation function in measurements of random particle systems.