Abstract: A series of MCM-41-supported Ni_xP catalysts was prepared by the solvothermal method using low-price triphenylphosphine as phosphorus material and tri-n-octylamine as coordinating liquid reaction system. They were characterized with X-ray diffraction, N₂ sorption, CO sorption, X-ray photoelectron spectroscopy and transmission electron microscopy techniques. The effects of initial P/Ni molar ratio on their structures and hydrodesulfurization performances were investigated in a lab-scale continuous flow fixed-bed reactor by feeding 1% of dibenzothiophene (DBT) in decahydronaphthalene. It was shown that Ni₁₂P₅ was primarily formed with a small amount of Ni₂P at the initial P/Ni molar ratio of 0.5. When the initial P/Ni molar ratio was higher than 0.5, pure Ni₂P phase was generated, and its crystal size decreased, and thus, its dispersion increased with the increase of initial P/Ni molar ratio. At 613 K, 3.0 MPa, H₂/oil ratio of 500 (volume ratio), and weight hourly space velocity of 2.0 h^-1, the DBT conversion nearly reached 100% on both the Ni-P (6)/MCM-41 and the Ni-P (10)/MCM-41 samples.