To study the effect of soft segments of thermoplastic polyurethane elastomer (TPU) material on the sealing performance of hydraulic cylinders,a series of TPU materials were synthesized by polybutylene adipate diol (PBA),polycarbonate diol (PCDL),polycaprolactone diol(PCL),polytetrahydrofuran ether diol (PTMEG),diphenyl methane-4,4′ -diisocyanate (MDI) and hydroquinone dihydroxyethyl ether (HQEE).The effects of soft segment types on physical and mechanical properties,friction and wear properties,hydraulic oil aging properties and sealing properties of TPU materials were studied.The results show that the four kinds of TPU materials synthesized by four soft segments have good physical and mechanical properties.PBA-type TPU material has the best wear resistance,and the friction coefficient of the TPU materials synthesized by four soft segments under the condition of hydraulic oil lubrication is 0.05,indicating a lower friction coefficient.PCDL-type TPU material has the best tolerance to hydraulic oil and sealing performance.PCDL-type TPU material is an ideal material for manufacturing hydraulic cylinder seals.