Abstract: To study softening Tilapia backbone by high pressure steam cooking, with pH, cooking pressure, steaming time and material /water ratio for study factors, the hardness of Tilapia backbone was evaluated with its maximum bearable pressure on universal testing machine. Results of single - factor experiments and orthogonal experiments showed that the softening effect of backbone was the best with the treatment condition of pH6.5, pressure of 0.13MPa, steaming time of 75min and material /water ratio of 1∶1.Under this condition, the hardness of Tilapia backbone was 33.0N.