Concerning the problem of train-ground safety communication in the Chinese Train Control System (CTCS)-3 train control system, a new model for information interaction between Radio Block Center (RBC) and train based on Petri net theory was designed by using the hierarchical modelling idea, and the simulation tool of Colored Petri Net (CPN) tools was used to dynamically simulate the whole process of generating, encrypting and transmitting the transmission information between train and RBC. The designed model was mainly divided into three parts. Firstly, the Movement Authority (MA) was requested by the train. Then, the MA under full supervision mode was generated by the RBC. Finally, the MA was received by train through wireless network and the safety control of train was performed according to the MA. The dynamic simulation and state space analysis tools were used to simulate and analyze the proposed model. The simulation results show that, the designed model can meet the design requirements of train-ground information transmission with boundedness, activity, regression and fairness. The designed model can be used for safe transmission of train-ground information, reducing software design flaws.