The delay and dispersion of the packet train have been widely used in most network measurement tools. The timestamp of the packet is critical for the measurement accuracy. However, timestamping performed either in the application or the kernel layer would be easily affected by the source and destination hosts especially in high-speed network. Therefore, to evaluate the impact of the timestamp precision on the measurement, a high accuracy timestamping hardware system (HATS) based on NetFPGA was designed and implemented. With HATS, the deviation of timestamp accuracy among the application, the kernel and the hardware layers was analyzed.