Metal–organic frameworks (MOF) are recently developed coordination porous materials, and their unique structures are very conducive to catalytic reactions. In this paper, p‐benzenedicarboxylic acid (PBA)‐Ni2+ MOF materials (denoted as PBA‐Ni‐x, where x represents the initial ratio of PBA to Ni2+) were synthesized by a hydrothermal method and characterized by X‐ray diffraction (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and N2 gas adsorption. H2 gas was produced using the synthesized MOF as a photocatalyst and Eosin Y as a photosensitizer. The dependence of the special surface area and thickness of the nanosheets of Ni‐MOF on the initial ratio of PBA to Ni2+ (PBA/Ni2+) was investigated. The BET surface areas of PBA‐Ni‐1 PBA‐Ni‐2 and PBA‐Ni‐3 are 11.00, 24.61 and 13.04 m2 g−1, respectively. And the thicknesses of nanosheets are approximately 600–1000, 200–500 and 300–700 nm. Among the three materials, PBA‐Ni‐2 has the thinnest sheet‐like structure and largest surface area. Thus, it displays the highest H2 evolution rate of 20.0 μmol h−1. The noble‐metal‐free hydrogen production system is valuable for the application of MOF materials in photocatalytic water splitting.