Provided is a method of eliminating the dependence of methanol induced promoter on a single methanol carbon source for expressing foreign polypeptide. The method comprises activating the expression of the promoter requiring methanol induction by increasing the expression quantity of Mit1 polypeptide in cells of methylotrophic yeast, so that the promoter originally depending on methanol induction no longer depends on single methanol and can also express foreign polypeptide.