In recent years, China's "double surplus" trend has gradually returned to equilibrium. In the new situation, it is necessary to know the relationship and influence mechanism among China's current account, capital financial account and exchange rate. Using the monthly data of China's net exports, foreign direct investment (FDI) and real exchange rate from 2011 to 2019, this paper analyzes the dynamic relationship among them based on a Vector Autoregressive (VAR) model. The empirical results show that long-term causal relationships exist among the three variables. In the long run, either the increase of FDI or the real depreciation of RMB will improve the trade balance to some extent. The J-curve effect of RMB real depreciation is not obvious, which means the time lag of depreciation for improving trade balance almost does not exist. Moreover, the export volume is not the factor mainly affecting FDI, but the change of real exchange rate would cause great fluctuations of FDI. So, the value stability of RMB is more conducive to attracting FDI, compared with its depreciation. The balance of trade surplus is an important source of RMB appreciation pressure. On the contrary, the increase of FDI will cause RMB devaluation in the long run.