Ba0.6Sr0.4TiO3(BST) thin films were prepared by radio frequency magnetron sputtering method and the effect of the substrate,annealing temperature and film thickness on the voltage withstand property was studied.The result shows that the BST thin films deposited on LaAlO3 substrates has smoother surface and higher voltage withstand property.The crystalline grain size of the BST thin film become larger with the annealing temperature increased from 750 ℃ to 850 ℃,and the electrical breakdown probability has been increased to some extent. In our results,750 ℃ is a more reasonable temperature for the films annealing.At the optimized process,BST thin film can withstand more than 125 V/μm.