It is a tough challenge for the geologists to model 3D shape of geological factors because of the complexity of geologic architecture and the insufficiency of exploration data. This paper presents research on modeling 3D shape of geo bodies and geo fields through 3D interpolation and iso surface constructing from limited and scatted exploration data. The Kriging algorithm，as its favorable for revealing asymmetrical and anisotropic distribution of data in the geo field

is used as the 3D interpolation method to convert the insufficient and random arrayed data set into sufficient grid data set. The iso surfaces are auto created from the scatter data through Marching cube algorithm. The above processes are achieved through VC++.net and OpenGL programming. By application of the above methods

the 3D iso surfaces of ore grade from drill data and inversely deduced resistance from magnetotellurics surveying data are simulated. Compared with the traditional methods

this produces for us good results and can be used as more convenient and effective tools for 3D visualization in geo exploration.