A modeling method of a cutting force model is provided, including: using a cutting tool to cut a unidirectional fiber reinforced polymer along a circular path; using a measurement member to measure the cutting force on the cutting tool corresponding to the angle between the feeding direction of the cutting tool and the fiber direction of the unidirectional fiber reinforced polymer; and obtaining the functions of the cutting force coefficients in a formula according to the measurement result of the measurement member. With the modeling method, a mechanistic force model can be rapidly established to predict approximate cutting forces of the cutting tool in use.