Device capable of simultaneously measuring plank constant and work function and measurement method thereof

A device capable of simultaneously measuring a plank constant and a work function and a measurement method thereof relates to the technical field of measuring the plank constant and the work function. According to the device capable of simultaneously measuring the plank constant and the work function and the measurement method thereof, the inside of a negative holder is respectively provided with a phototube, a micro-current amplifier and a light-emitting diode ( LED) emitting element, the outside of the negative holder is respectively provided with an adjustable LED power source and a testing instrument, the phototube is connected with the micro-current amplifier and the testing instrument respectively through guiding lines, the micro-current amplifier is connected with the testing instrument through guiding lines, and the adjustable LED power source is connected with the LED emitting element through guiding lines; and the LED emitting element is provided with a plurality of LED lights. The device capable of simultaneously measuring the plank constant and the work function and the measurement method thereof are simple in structure, good in testing efficiency and pollution on human body can be avoided and energy can be saved.