The utility model provides an AC/DC and impact property simulation test device of a large ground network. The simulation test device mainly comprises a rectangular simulation tank, an equivalent reduced ground network model, AC and DC test power supplies, an impact current generator and a precise positioning system. The simulation test device is characterized in that: metal grids are laid on the four inner walls and the bottom of the rectangular simulation tank to form a network shaped backflow electrode, a liquid medium is injected into the tank; the ground network model is designed and produced according to the purpose and content of the test; the precise positioning system is composed of an electric moving vehicle and a total station; the cooperation of the electric moving vehicle and the total station facilitates the fixed-point measurement on any points in the rectangular simulation tank. The AC/DC and impact property simulation test device not only can satisfy the test research on the DC, work frequency, and impact ground property of the large ground network, but also can extend the fields such as the test research on the effect of the AC and DC systems on aquatic organisms and metal pipes and the corrosion characteristics. The AC/DC and impact property simulation test device has the advantages of simple operation, large power supply capacity, durableness, flexible modification etc.