The spring steel produced by China Steel Corporation has been satisfactory to customers. However, with the requirements for advanced applications getting more and mo re critical, improvements to the central quality of the steel by overcoming the defects of central segregation and cavity become necessary. First of all we adopted norm al process trials to select suitable variables, and then chose 3 process variables, namely secondary cooling water, cast velocity and soft reduction pattern, which affect the central quality for the analysis by Taguchi method. A L4(2^3) orthogonal array design was performed on the spring steel grade 9254/9260. Finally, an optimal process was attained, with which the central quality of spring steels was greatly improved.