By the features of parallel processing and hardware acceleration, multi-core network processor (NP) are becoming the mainstream platform of next generation network edge devices. In order to take advantage of multi-core NP platform and improve the performance of TCP pacing algorithm, this paper proposes an implementation of TCP pacing algorithm based on multi-core heterogeneous systems. The implementation provides a timing method that is more accurate than the clock interrupt-based timing in Linux kernel. And it is an optional alternative to the traditional TCP implementations. The experimental test based on prototype platform shows that, the smoothness performance of the proposed implementation is improved by 27.78%, and the resource utilization is also better than the traditional scheme.