The embodiment of the invention provides an automatic compilation method of a train working diagram based on underbody duplexing, and relates to the technical field of train running control. The automatic compilation method includes steps of configuring basic parameters for compiling the train running diagram; configuring a train operation plan according to the basic parameters; building up an optimal model of the train working diagram according to the basic parameters and the train operation plan; applying a mixed integer linear planning algorithm to solve the optimal model of the train working diagram, and acquiring the train working diagram based on the number of the underbody in operation. The method improves the compilation efficiency of the working diagram; the automatically compiled train working diagram can meet the returning time, safety interval, train order, underbody use, and other restriction conditions, guarantee the feasibility of the working diagram, reduce the operation cost, and decrease the passenger waiting time; besides, the method can meet the demand of frequent adjustment of the train working diagram under a refined management of an urban rail system.