In order to solve the problems of excessive quality and poor dynamic characteristics of the direct blowing castable vibration forming fixture,the mathematical model of fixture optimization was established,the topology optimization was used to optimize the distribution of fixture structure materials.On the basis of topology optimization,sensitivity analysis was used to screen the size with greater relevance as the optimization variable.The response surface model was established based on Kriging method,and multi-objective genetic algorithm was used to optimize the size of the vibration fixture.The fixture quality after two optimizations is reduced by 12.7%,the first order natural frequency is increased by a total of 2.8%.And the scanning frequency vibration response simulation analysis of the optimized fixture structure was conducted to verify the effectiveness and rationality of the optimized design of the fixture,effectively solving the problems of experimental resonance and excessive fixture quality that are prone to occur in the design of the vibration forming fixture for direct blow pipe castable.