The magnetic phase transition and the magnetoresistance (MR) in bulk intermetallic PrGa compound are investigated experimentally. Two successive magnetic transitions, ferromagnetic (FM)-antiferromagnetic (AFM) transition and AFM-paramagnetic transition, are observed at T1 = 28 K and T2 = 36 K, respectively. It is found that the PrGa compound exhibits a field-induced metamagnetic transition from AFM to FM state and a considerable change in lattice constants in a temperature range of 28-36 K. Accompanied with the AFM-FM transition, a negative MR occurs, and the maximal MR values are ∼30% and ∼34% at 28 K under the fields of 1 T and 5 T, respectively.