The disposable plastic centrifuge tube has a tube cover, which is used to prevent the leakage of the sample, especially for the radioactive or highly corrosive samples. The tube cover also has a function of preventing the sample from volatilizing and supporting the centrifuge tube to prevent the deformation of the centrifuge tube. When selecting this point, we should also pay attention to check whether the pipe cover is tight, and whether it is tight during the test, so as to achieve inversion without leakage.