A prototype frame base expert system ESDIR (Expert System for Design of Industrial Robot) has been built. For a given specification and application, the design procedure of ESDIR is first to synthesize and evaluate the robot geometry. The synthesis is accomplished by on-line interfacing with external CAD programs written in conventional language. Then the selections of power drive, actuation, and coordination method are recommended. Iterations between design and re-design are needed in ordinary design procedure. This is time consuming and error-prone. ESDIR is one of the efforts toward design automation trying to minimize the cycle time and improve design efficiency.