Based on the shortcomings of the Hofmann water electrolyzer, a new type of portable water electrolyzer with obvious phenomena, easy self-fabrication, and low cost was designed through literature analysis and experimental improvements. This device utilizes 304 stainless steel countersunk self-tapping screws as electrodes, plastic pipettes, and PVC sealing bags to form a closed reaction vessel. Two 9V batteries are assembled into a battery box, effectively addressing issues such as slow electrolysis rate, high instrument center of gravity prone to breakage, easy electrolyte leakage, and too fast gas escape in the Hofmann water electrolyzer. The improved device is not only lightweight and portable, but also has a fast electrolysis rate, controllable airflow, and less prone to electrolyte leakage. Additionally, the reaction vessel can be electrolyzed immediately upon placement, eliminating the need to carry multiple instruments such as extension cords and student power supplies. Through teaching practice, it has been proven that this device can achieve relatively ideal experimental results and has good promotion value.