Abstract: In order to effectively solve the temperature controlling problems in staining process of paraffin section preparation,combing the advantages and disadvantages of the traditional staining jar, a temperature controllable staining jar is developed. An inner tank, a lid actively connected to the inner tank and an outer tank compose the staining jar. The inner tank is made with stainless steel; three devices are set around the outer tank, containing a chamber inside which is used to contain the inner tank,heater devices at bottom and internal sidewall, as well as a controlling module, a display module and a timing module outside which are connected to the heater devices by wires. During the staining process, the display module exhibits the temperature of the staining solution in inner tank; the temperature can be maintained in a range of 40-80 ℃ by regulating the controlling module; the staining duration can be preliminary set by using the timing module that can alert the experimenter at the end of the timing, which prevents the paraffin section from being stained too deeply or too lightly.