This paper makes positive study on long- term Renminbi exchange rate change trend, uses co-integration model to build equilibritrn relationship between real exchange rate and productivity and between govemmental consumption and trade condition, and uses error - correction model to examine short - term dynamic adjustment process d real exchange rate. The result indicates that productivity change play an important role in Renminbi real exchange rate change irrespective of short - term or long- term and that real exchange direction is reversal of Balassa - Samuelson Effect anticipation. This is because the anticipation is not suitable for economic development period of China, because labor force unlimitedly supplies, because govemmentconsumption and trade condition affect Renminbi exchange rate change trend. Balassa - Samuelson Effect anticipation is not suitable even in long-term condition. Govemment can use financial expenditure to affect real exchange rate to vibrate in short - term and long- term in order to help Chinese product to have price advantage in international market.