Based on New Trade Theory, this paper collects and collates Agricultural Trade Data of HS 6-digit that amounts to 727 pieces from 1996 to 2013. Drawing lessons from the innovative research methods of analyzing export growth, the paper explains the reason why China’s agricultural exports to Japan show a growth in ternary margins: extensive, price and quantity margin, and then analyzes the extent of China's export competitiveness of the ternary marginal variables. Confirmed that studies have shown that: extensive margin is not the dominant reason for the growth that China’s agricultural exports to Japan, that is, China’s pattern of the amount of win is unchanged essentially, quantity margin could enhance the competitive ability of China’s agricultural exports effectively in the short term; price margin plays a stronger role in driving China’s agricultural exports forward, what's more, it has effect on competitive advantage significantly.