Aiming at the problems of slow start-up response,concentrated speed and initial motion impact of unidirectional drive caliper logging tool,a new structural caliper logging tool with bidirectional drive characteristics was proposed,and the vectorization modeling solution and working behavior analysis (motion performance simulation and measurement performance simulation) were carried out for the bidirectional drive process of its pushing system (to realize the expansion and contraction of measuring arm).The physical modeling and theoretical research of the bidirectional drive logging tool pushing system were carried out.With the parameters (speed and displacement) of the bidirectional drive lead screw system as input,the motion performance parameters (displacement,speed and acceleration) of the logging tool pushing system were parameterized by using the complex vector method.Then,taking the actual bidirectional drive pushing system as an example,the motion characteristics were solved theoretically,and the motion curves of the pushing rod port and the pushing pin were obtained,and the matching characteristics of the bidirectional drive speed were studied.Finally,the working behavior of the logging tool was analyzed based on ADAMS,and the simulation results were compared with the theoretical results.The results show that the simulation motion curves of the pushing system are in high agreement with the theoretical analysis curves,which prove the correctness of vectorization modeling of the pushing system of logging tool.