Ethernet transmission has high requirements of clock synchronization accuracy. Factors such as switching between different clock domains and data bit width conversion will enlarge the jitter amplitude of the time stamp in the Precision Time Protocol (PTP) frame, resulting in the problem of clock asynchronization. In order to solve this issue, this paper proposes a method that can eliminate the jitter of the time stamp to improve the accuracy of the time stamp-uniform envelope rate characterization, which ensures the uniformity of the Ethernet transmission data distribution by depicting a uniform data envelope. Therefore, the time stamp jitter can be eliminated and precise clock synchronization is achieved. Experimental data shows that after the data is characterized by a uniform rate envelope, the jitter amplitude of the time stamp is significantly reduced with obvious the jitter elimination, and the jitter range remains within ±20 ns.