High temperature proton exchange membrane fuel cells (HT-PEMFCs) can operate over 100 °C without humidification, which avoids the catalyst poisoning and enhances the efficiency of the power conversion. However, the classic phosphoric acid (PA) doped polybenzimidazole (PBI) still remains the challenge in the trade-off between mechanical strength and proton conductivity. The γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH560), as a crosslinking agent, is widely used to improve the mechanical properties of membranes. Although it can enhance the mechanical strength of PBI membranes, it sacrifices the hydrogen of imidazole groups, resulting in a decrease in proton conductivity. In this present work, silane-crosslinked PBI proton exchange membranes (PEMs) were synthesized by the reaction between the pyridine-bridged PBI containing different hydroxyl (-OH) content with KH560. Through comprehensive structural characterization of the polymer and model compound, it has been determined that this crosslinking method does not compromise the N–H acidic sites on the imidazole ring. The crosslinking agent KH560 provides additional hydroxyl groups to PBI and participates in the construction of hydrogen bonding networks after the ring-opening reaction. It was found that the addition of pyridine and hydroxyl groups could promote the phosphoric acid uptake, and the appropriate degree of silane crosslinking could maintain the PBI membranes with reasonable mechanical properties. Proton conductivity and HT-PEMFCs performance of the obtained crosslinked films were further enhanced with the dimensional stability, thermal stability and mechanical properties. Among them, CPyOPBI–OH–20 presented the best overall performance, exhibiting the highest proton conductivity of 0.095 S cm−1 and the maximum power density of 767 mW cm−2 at 180 °C under the anhydrous condition, which was 4.2 times that of OPBI (182 mW cm−2). Display omitted •Silane cross-linked PBI membranes were fabricated by the reaction between the epoxy group of KH560 and the hydroxyl group of PBI without consuming the N–H on the imidazole ring which was proved by model reaction.•The CPyOPBI-OH-20 membrane exhibited a peak power density of 767 mW cm−2 at 180 °C without humidification.