The invention discloses an ejector rod positioning mechanism of a temperature controller. The temperature controller comprises at least one body, an elastic sheet, a fixed sheet, an ejector rod and a dual-metal sheet, wherein one end of the elastic sheet is fixed in the body while a connecting point is fixed on one side of the other end of the elastic sheet; the fixed sheet is fixed in the body and is tightly close to the connecting point of the elastic sheet; the dual-metal sheet is placed at the opening end of the body; one end of the ejector rod props against the elastic sheet while the other end is in contact with the dual-metal sheet; a through hole is formed in the fixed sheet; and the ejector rod passes through the through hole of the fixed sheet. According to the ejector rod positioning mechanism of the temperature controller provided by the invention, the fixed sheet used for positioning the ejector rod is fixed in the body; without being shielded, such as by the existing guiding cover, a thermostat only needs measurement of one time, and the distance between the elastic sheet and the fixed sheet can be accurately measured; and then the proper ejector rod is selected according to the distance, so that measurement procedures are less.