Micromotion induced by radio-frequency (RF) field contributes greatly to the systematic frequency shifts of optical frequency standards (OFSs). Although the micromotion is compensated to the best degree before each experiment, the influence of micromotionwill gradually appear with the shift of stray electric field during the experiment, which requires continuous compensation. To overcome this problem, indium tin oxide (ITO) conductive glass is used to optimize the vacuum system in linear ion trap system to restrain the shift of stray electric field. By measuring and calculating, the stray electric field shift is minimized to 1.63 μV·m－1·s－1, after optimization, which is around 1/40 of the previous work 57.7 μV·m－1ots－1, so that the influence of micromotion can be negligible during the long-time experiment, and the effective time of experiment can be significantly increased.