Rubber packers play a crucial role in extracting unconventional oil and gas reserves using hydraulic fracturing methods. This article conducts finite element modelling and analysis of one typical rubber packer, predicts its sealing performance and optimises its structural parameters. The key structure parameters of the rubber packer are regarded as design variables and the optimisation is carried out using the design of experiment (DOE) analysis and the full factorial design methods through Isight software. This study investigates the influence of major structure parameters on sealing performance. The optimal structure parameters for achieving the best sealing effect are attained, which are chamfer angle at the rubber sleeve end of 47.5°, rubber sleeve thickness of 22 mm, rubber sleeve height of 75 mm and rubber sleeve end width of

11 mm, respectively.