Denitrogeneration of petroleum products can reduce NOx emission during combustion, and relieve the poisoning of catalysts. Because of their high catalytic activities and excellent stabilities, transition metal phosphides exhibit great potential as novel, promising hydrodenitrogeneration (HDN) catalysts. Based on a periodic slab model, we investigated the adsorption and C―N bond cleavage mechanism of aniline on MoP(001) surface by density functional theory (DFT) calculations. The results show that aniline adsorption prefers a flat configuration, with larger adsorption energies, in which the C―C and C―N bonds are activated. The direct C―N bond cleavage mechanism of aniline proceeds mainly via deamination with co-adsorbed H2, producing benzene and ammonia. The C―N bond cleavage mechanism for adsorbed cyclohexylamine proceeds via deamination, with co-adsorbed H, and the main products are cyclohexene and ammonia.