This study choiced the manganese dihydrogen phosphate, antimony trichloride, tartaric acid, phosphoric acid, sodium molybdate, polymer-A and polymer-B as the main raw materials in the the system of blacken phosphating solution for metal surface. By orthogonal testes the optimum process conditions were optimized out namely: manganese dihydrogen phosphate was 8.0 g/L, antimony trichloride was 6.0 g/L, tartrate was 6.0 g/L, phosphoric acid was 50 g/L, sodium molybdate was 1.0 g/L, polymer-A was 1.0 g/L, polymer-B was 1.5 g/L. Test results show that the blacken phosphated film is tight uniform, and has good adhesion.