Ethernet has become the most widely used LAN technology because of its high communication rate and low cost. However, with the increasing demand of real-time network in automotive and aviation fields, traditional Ethernet has been difficult to meet its performance. Based on the precise time protocol (PTP) of IEEE 1588 protocol and Timestamp Technology, an Ethernet controller with high-precision time synchronization is designed in this paper. In addition to meeting the basic Ethernet communication function, the controller can also calculate the delay and correct the time with high accuracy. The controller adopts a point-to-point transparent clock and uses PTP delay algorithm to calculate the information in the data packet.