Hello i am a medical student studying in China recently my X visa has expired .

You should first prepare the relevant materials for student X type: the application form, a recently-taken half-length color photo, your passport and its copy, JW form, the admission letter from the school, physical examination report, and your personal statement as well as other documents the consular officers consider necessary.
And then submit the application to the embassy of PRC to apply for the X type.