Three-dimensional model has been showing extensive demand and vitality in modern industrial design, artificial intelligence and software design fields. Traditional feature extraction methods merely depend on model surface feature, which could not sufficiently satisfy complex model feature extraction needs. In order to improve the accuracy of model feature extraction, a 3D model feature extraction method with high discrimination was proposed based on spectral analysis and light propagation attributes. Firstly, the probability of light transmission, scattering and reflection when light propagation in different medium was quantitatively analyzed with scattering coefficient, absorption coefficient and anisotropy parameters. Secondly, the Monte-Carlo method was used to simulate light propagation in complex 3D model, where different feature statistics including angle, distance and energy were obtained to complete feature extraction. Then, the influence factors of photon beam number and constrained space shape were tested for optimal parameters determination. Finally, the feature extraction effectiveness was evaluated on retrieval precision, recall and E-measure. The results showed that the feature extraction accuracy sensitively varied with constrained space shape and the optimal constrained space for photon propagation was sphere; The feature extraction efficiency decreased with more photon beams, and within basic accuracy requirement, 10 000 to 25 000 photon beams were the optimal simulation number; The feature extraction accuracy of proposed method was higher than the wavelet transform, distance-angle and D2 distribution methods, which is more suitable for offline feature extraction of complex 3D models. The proposed simulation method of feature extraction broadens spectral analysis application, which could extract the integrated feature between model surface and internal structure, promoting model feature extraction research.