This tutorial on surface design of a turbine rotor casing with multi blades helps the engineering students and working professionals to know completely the procedure involved in the CATIA surface design of a casing. In the process of learning this surface design of a casing of a multi bladed rotor, they will know about various commands such as circle, plain with offset, project 3D element, conveting the projection into axis, three point arc, coincidence command, revolution command , switching to part design and learn about thickness command.