In order to obtain the digital model of noncircular gear mechanism, based on reverse engineering technology, some relevant parameters were obtained directly through the existing products.Combined with the motion principle of the gear mechanism, computer programming was used to calculate relevant parameters of pitch curve. Finally, according to the parameters obtained, the digital model of noncircular gear was established.This method greatly simplifies the complexity of the design, facilitates the establishment of digital model,and plays a positive significance to the performance optimization and upgrade of the model in the late period.