Nowadays, carbide end mills are widely utilized in the aluminum, titanium and steel cutting industries, so the more and more high-precision requirements to design of cutters are provided by users. Meanwhile, in order to finish the simulation and analysis of cutting processing, it is also important to design more free-control geometry model, and then transit into the CAD/CAM systems. For this purpose, many research works have been successfully conducted on optimizing the geometry model of cutters to get more real and easy controlled geometry;​ however, another critical factor, there are still more space to optimize the geometry model of cutters. To finish this task, in this work, first, a method has been established and implemented in the MATLAB to convert mathematic model into a free-form geometry model. Then, an accurate calculation system of area moment inertial of cutter is built. Finally, a detailed discussion on the cutting force of end-mills is provided, based on cutting simulation software. The major contributions of this work include the free-form end-mill modeling, which can render the 3-D geometric model of an end-mill in CATIA system, and a type of calculation of cutter area moment of inertial. This work can be used, together with an existing cutting force calculation method, to accurately predict cutting force during milling in order to get better geometry model of cutter. Meanwhile, solid modelling of the helical cutting tool can be carried out with computer graphics programming. It can also provide more precise 3-D solid models of end-mills for machining simulation by using finite element software.