Abstract: AZ31 magnesium alloy billets were prepared by spray forming technique, then the alloy billets were hot rolled into compact plates. The microstructure and mechanical properties of the alloy were investigated. The result indicates that the spray formed alloy has a fine microstructure with an average grain size of 20 μm. The finer and mechanical properties were gained by the compacted processing, dynamic recrystallization and annealed static recrystallization. The fracture surfaces of the as-hot rolled sample show a typical brittle fracture character while the as-annealed sample displays a mixed mode of brittle fracture and tough-hess fracture.