The invention discloses an informatization modeling method for an earth-rockfill dam based on VB and CATIA. Secondary development is carried out on the basis of the VB language and the CATIA, the VB calls the CATIA, and modeling is carried out. The modeling method comprises the following steps of establishing a three-dimensional terrain model on the basis of existing topographic and geological data; linking the VB with the CATIA; designing a VB interface comprising location control parameters and shape control parameters in the VB; writing codes in the VB and creating a dam axis according to endpoint coordinates of the ends of the dam axis; writing codes in the VB and completing design of a dam body; running a program, inputting the parameters, and generating a model. A traditional design mode is abstract in expression and poor in error-correcting capability, and greatly limits improvement of design efficiency. According to the informatization modeling method based on the VB and the CATIA, the characteristics of secondary development, parameterization and three-dimensional visualization of software are utilized, the disadvantage of the traditional water conservancy project design mode can be avoided, and the efficiency is improved.