This paper considers the influence of ERP's implementation on the enterprise internal control effect with the method of empirical, It is based on the data of the enterprises which implement ERP in 2008 as the research object, take internal control's three big goals as the starting points and are in view of ERP implementation process in correlation factor. The findings suggest that ERP's brand and number of years of implementation that can obviously promote enterprise's business efficiency are positive to the enterprise business efficiency. But the ERP's brand is negative to the effectiveness of operations. Meanwhile, the implementation age and the enterprise illegal activities are remarkable related. It means that with years of implementation increased, the artificial operation to the system data would possibly happen through the social familiarity with ERP system. In the end, it causes enterprise illegal behavior and unlawful act happen.