Aiming at the problem that asymmetric delay will seriously affect the clock synchronization accuracy under high network load, a linear estimation method of clock model is proposed to improve the clock synchronization accuracy under high network load. Firstly, a linear model is established for the master and slave clocks; and then the slave clock uses the master clock as the reference clock to process the four timestamps obtained in the current synchronization cycle, and combine them into two endpoints, through at least two synchronous cycle timestamp information and characteristic of the endpoint, find linear upper bound function and linear lower bound function from the model of the slave clock, the linear function of the slave cl-ock in the current synchronization cycle is determined by the mean value of the two, and the timestamp value is estimated a-ccording to the linear function, so as to estimate the master/slave clock offset in the current synchronization cycle. In order to verify the effectiveness of the proposed algorithm, a clock synchronization module based on the open source software Linux PTP is used to perform experimental verification and synchronization accuracy test on the DAC model and the proposed algor-ithm. Experimental results show that the clock model linear estimation algorithm avoids the continuous compensation in the sa-me direction for the local clock frequency, and achieves 23.48ns clock synchronization accuracy while making up for the defi-ciency of the DAC model.