We present a throughput enhanced transport approach, Multi-Path Overlay Transmission (MPOT), which builds an overlay network on top of the IP underlying network, and transmits different data parts via different overlay paths. This multi-path transmission approach in overlay network can keep away from the bottleneck link, and increase the throughput with multiple overlay paths. We also introduce the pipeline buffering and dynamic path switching to improve the performance of MPOT. The performance of the MPOT scheme is verified and compared to the standard single-path IP transmission using ns simulations. It is shown that MPOT scheme greatly outperforms standard single-path IP transmission for file transfer and real-time media transport when some bottleneck links are located in the IP single-path.