The PH tester used for teaching adopts a pen design, with one click power on, and a full range reading of 0-14 can be obtained in 3 seconds, with an accuracy of ± 0.1. The high-definition backlit screen can switch between pH and temperature dual displays, and supports automatic temperature compensation. The probe is equipped with replaceable glass electrodes and a plastic protective cover to prevent falling and drying. With the three-point calibration of buffer solution 4.01/7.00/0.01, students can quickly determine the acidity and alkalinity of tap water, beverages, soil extracts, etc. The data can be locked for easy recording. The whole set is packed into a storage box, suitable for both classroom and field exploration.