The paper establishes a model of real exchange rate decision based on NOEM. Based on theoreticalmodel and realities at home and abroad to expand，the paper makes an empirical test about the five factors impacting on the RMB real exchange rate fluctuation. The results show that the RMB exchange rate formationmechanism reform has the strongest explanatory power for the RMB real exchange rate fluctuation，terms of trade and relative money supply has the second explanatory power，relative productivity’ s explanatory power is limited because the channel of B-S effect is not smooth in China, net foreign assets has the weakest explanatory power and can only lead to real exchange rate fluctuation slightly. The paper concludes that the RMB is not suitable for excessive free-floating，progressive flexibility should be continued to maintain for relatively stable of RMB real exchange rate. Monetary policy and industrial structure optimization policy can become a means of real exchange rate adjustment. Keywords:RMB; real exchange rate fluctuation; exchange rate formation mechanism reform; B-S effect; NOEM framework