The theories of fracture toughness measurement for three J-integral test methods, including unloading compliance method, normalization method and S_pb separation parameter method, are summarized, and the three methods are used to test the fracture toughness of a metal material. It is found that all the three methods can obtain effective J_IC values. The J_IC value obtained by the unloading compliance method is slightly greater than those obtained by the other two methods, and the result obtained by the normalization method is slightly smaller than those obtained by the other two methods but close to that by the S_pb separation parameter method.