High strength and high modulus polyethylene (UHMWPE) staple fiber and softwood pulp were used as raw materials to prepare UHMWPE fiber paper-based composites materials by wet forming technology combined with resin impregnation and hot pressing. The effects of base paper preparation technology and hot pressing technology on UHMWPE fiber paper-based composite materials were investigated. The results show that, in a certain range, the mechanical properties of paper-based composites materials are improved and the pore size distribution is more uniform with the increase of quantity, beating degree of softwood pulp and proportion of softwood pulp. Phenolic resin impregnation and hot pressing treatment can further improve the mechanical properties of paper-based composite materials (tensile index increased by 3.8 times), and has lower dielectric constant and dielectric loss factor.