Using panel data of 28 provinces in China during 2003—2014，this paper calculates the enterprise income tax effort and analyzes the influence factors of the tax effort by the stochastic frontier analysis method. The results show that the average tax effort of enterprise income tax in each region during 2003—2014 was showing a wavy upward trend，but it still had a large room for improvement. At the same time，tax efforts varied greatly in Chinas different regions. As time goes by，the tax effort is improving spontaneously. Further results indicate that tax effort is negatively correlated with the tax collection centralization. The study also demonstrates the positive relationship between tax effort and economic development，the central tax administration centralization，the level of economic development，trade openness，regions pubic finance expenditure scale and enterprise income tax as percent of tax revenue.