In order to solve the problem of linear demodulation for phasemodulated microwave photonic link, a theoretical study of highlinear phase demodulation with optical phaselocked loop (OPLL) is carried out. A detailed link model is established, and taking full account of the influence of noise and nonlinear distortion, the variation trend of key parameters of the link was derived. And also, the key parameters of the link were simulated based on the parameters of actual link devices. Simulation results show that based on the OPLL, the dynamic range of the link can reach 127dB·Hz2/3 at 200MHz RF, which is nearly 20dB higher than that obtained by the traditional intensity modulation method, providing a reference for applications of largedynamic microwave photonic link.