Wide-band-gap BiPO4 (BPO) is a promising candidate for photocatalytic degradation of highly stable benzene exhaust. To reveal the effect of the morphology and the oxygen vacancies of BPO on the degradation of benzene, a series of monoclinic BPO samples with the common reported rod- (BPO-R), sheet- (BPO-S), urchin- (BPO-U), and dendrite-like (BPO-D) morphology were synthesized and some oxygen vacancies were introduced in BPO-D. The samples were then used for photocatalytic degradation of gaseous benzene and the mineralization rate of benzene over the samples decreased in order BPO-D (258.6) > BPO-S (48.0) > BPO-U (21.0) > BPO-R (7.3 mu mol h(-1) m(-2)). BPO-D with a dendritic morphology showed the highest activity. The highly energetic (002), (012), and (031) facets and the oxygen vacancies make great contributions to the high performance of BPO-D, which favor the absorption of BPO-D in long-wavelength range, the adsorption of reactants, the formation of O-2-(.) and eventually the interfacial degradation of benzene. The ESR and scavengers tests indicated that O-2-(.) and the photogenerated holes are the main active species responsible for the degradation of benzene. This work suggests that increasing the proportion of high-energy crystal facets and introduction of oxygen vacancies are effective strategies to improve the photocatalytic performance of BPO.