Under the background of China's deepening integration into global production networks, how to evaluate China's real export competitiveness and observe its evolution direction and routes needs to take the quality and quantity of trade into account comprehensively. This paper combines TiVA method with MPI measuring industry trade competitiveness to construct market penetration rate index of trade in value added (MPIVA) based on import market of final products, and then measures changes in China's export competitiveness and the causes within global production networks. It arrives at the results as follows:firstly, China's value-added export competitiveness within GPN has been increasing, but its speed has slowed down; China's value-added export competitiveness is rising in most industrial markets, among which manufacturing industry appears faster, while value-added export competitiveness in the service industry is also rising; secondly, both the increase in intra-industry value-added export and the transfer to industries with high-level value-added account for China's increase in value-added export competitiveness, however, the main cause lies in export intra-industry effect rather than inter-industry effect; thirdly, China's industrial export competitiveness in value added is not derived from the direct value-added effect of export industries themselves, but from indirect value-added effect of upstream industries, and China's manufacturing export is at the low end of the global value chain and there is much more space for growth. It provides useful implications and reference for the improvement of trade position of China's export industries in the global value chain and the optimization of trade structure of export industries.