In order to obtain the analytical expression between objective functions and design variables for space deployable truss antenna during the structure optimization,prediction model of optimal parameters was built based on BP neural network.According to the truss structure and training principle of neural network,network model was established.Optimal parameters were calculated by using the finite element software ANSYS,and the training samples were obtained by orthogonal design.Adjusting the transfer function,the number of hidden nodes and training algorithm,prediction model was constructed,which satisfied the error requirement.Generalization capacity of neural network was tested by means of testing samples.The results show that predictive values of neural network agree well with finite element calculation results,which the relative error is within 10%.Moreover,the run time of model is shorter than that of ANSYS,which only needs 0.13 s.This model can predict optimal parameters more accurately and provide a theoretical reference for the structure optimization.