Abstract: At present, Vacuum grease Pistons are commonly used for domestic laboratories sample preparation device of water hydrogen isotope. In sample preparation process, relatively more sample are used, and the degree of vacuum is low, and the samples are easily contaminated. Contraposing these defects, when the device was developed, hydrogen isotopes in water system no-grease vacuum sample preparation device was first used in the country. The tests confirm that compared with traditional Pistons, the no-grease Pistons have the characteristics of little pollution among samples, easily vacuuming, reducing the amount of samples, easily operating, and so on. This device does not only meet the test specifications, but also can be used for the samples preparation of hydrogen isotope test analysis in water.