Abstract: Taking results of fluorescent penetration inspection of titanium alloy precision casting as research objects, the effects of pickling on the size of surface defects of fluorescence display were discussed by using multiple times pickling methods. The experimental results show that the pickling can fully expose the surface defects in fluorescent penetration inspection, which is beneficial to the detection of defects. Therefore, in the manufacturing of titanium alloy castings, it is necessary to arrange pickling reasonably before the fluorescence penetration inspection, and strictly control the amount of unilateral pickling and the number of pickling to ensure the reliability of the nondestructive inspection results.