The method of electro-hydraulic proportional controlling means matched by pump valve compound flow rate was proposed to achieve flatpushing while designing the national largest faceshovel hydraulic excavator with the bucket capacity of 15 m3 and machine weigh of 260 t. The ratio of hydraulic cylinders-flow rate was ascertained by computer coordinate control during the flat-pushing process, the co-simulation research of dynamics of mechanical systems and hydraulic system in developing mining excavators flat-pushing process was carried out by using the software of ADAMS and AMESim. The displacement, velocity and pressure of arm mining process in various hydraulic cylinder on the small excavator were validated by the experiment. It is confirmed that co-simulation research methods can accurately simulate the practical working environment of excavator. 