Removal of organic pollutants from water bodies by photocatalysis has broad application prospects in the field of sewage purification. In this study, the quaternary BiMnVO₅ was synthesized by hydrothermal method and solid-state reaction, respectively. The morphology, structure and optical properties of the catalysts were characterized, and the electronic structure was calculated. Results showed that the hydrothermal method can rapidly synthesize pure BiMnVO₅ with high crystallinity. BiMnVO₅ is a semiconductor with a direct band gap of 1.8 eV, which is consistent with the results of first-principles calculations. Analysis of the density of states further reveals that the optical absorption band are attributed to the transitions from Mn3d/O2p to V3d. The photocatalytic results show that the BiMnVO₅ synthesized by hydrothermal method exhibits the highest catalytic activity. About 98% Methylene Blue (MB) is degraded when exposed to visible light for 4 h. The hydroxyl radicals and photo-generated holes are proved to be the main active substances in the photocatalytic process. After 5 cycles, it still maintains capacity of degrading 85% MB in 4 h under visible light irradiation, while its morphology and structure remain unchanged, which indicates BiMnVO₅ a good photocatalyst with reliable stability.