Objective: From the biomechanical view, to probe the changes of plantar pressure under transverse arch of forefoot of hallux valgus foot. Methods: By applying the foot pressure measurement system developed by us, we had measured the plantar pressure of 32 normal and hallux valgus foot respectively and then did the statistic analysis of acquired data. Results: With the increasement of bearing ratio, the pressure under the middle metatarsals of hallux valgus foot has a more rapid change. Comparing with that in normal foot, there was significant difference. Conclusions: It is proved from biomechanical view that there is transverse arch in the forefoot of normal and collapsed transverse arch in the forefoot of hallux valgus foot.