The invention provides a method for calculating winding hot-spot temperature and top oil temperature of an oil-immersed transformer. The method comprises the following steps: S1, establishing a calculation model of the winding hot-spot temperature of the oil-immersed transformer, wherein the calculation model comprises nonlinear heat conductance, lumped heat capacity and two heat sources; and S3, calculating the winding hot-spot temperature of the oil-immersed transformer according to the calculation model through a formula defined in the specification. According to the method, the calculation precision of the winding hot-spot temperature can be effectively ensured and working practice can be accurately guided.