The invention discloses a measuring tool and a manufacturing method. The measuring tool comprises a transparent arc plate and heat-humidity ratio marks, wherein the heat-humidity ratio marks are formed on the transparent arc plate, and corresponding lines of the heat-humidity ratio marks point the circle center of the transparent arc plate. The measuring tool serves as a heat-humidity ratio scriber, and relevant lines and points can be directly marked on a psychrometric chart of humid air based on the carried mark values (i.e., the heat-humidity ratio marks), so that the operation time can be saved for users such as air conditioner design technology learners, teachers and beginners, and the efficiency and quality of working and learning are effectively improved.