The invention discloses a PVC door gasket with a migration-resisting function and a preparation method thereof. The PVC door gasket is prepared from the raw materials in parts by weight: 90-110 partsof PVC resin, 50-70 parts of a main plasticizer, 50-60 parts of a filling agent, 6-10 parts of a stabilizer, 1-2 parts of a lubricating agent, 0.5-1.5 parts of pigment, 0-0.6 part of a flame retardant, and 0.2-0.4 part of an assistant, wherein a plasticizer is a mixture of the main plasticizer and auxiliary plasticizers, and the main plasticizer is one or more of trioctyl trimellitate (TOTM), dioctyl sebacate (DOS) and dioctyl terephthalate (DOTP). Production efficiency of a first door gasket and a second door gasket is greatly improved, the processing cost is lowered, and meanwhile the molecular migration rate of the first door gasket and the second door gasket is greatly reduced; the PVC door gasket obtained by installing the first door gasket and the second door gasket is reasonable instructure, impact force received during door closing and opening is effectively relieved, airtightness is good, and wide application prospects are achieved.