Due to the low sensitivity and weak stability of the hydrogel flexible sensor, the sensitivity and stability of the hydrogel sensor were improved by designing a zigzag hydrogel with excellent resilience and a small cross-sectional area. First, a zigzag mold was prepared by 3D printing, and a polyacrylamide solution was cast into the mold for cross-linking. Then, a sensor based on the zigzag hydrogel was encapsulated with VHB double-sided tape and tested for human motion sensing. Finally, a sensor based on an unstructured sheet-like hydrogel was selected as a control group to verify the improvement in the sensitivity and stability of the hydrogel sensor by the serrated hydrogel. Experimental results showed that the sensor based on the zigzag hydrogel exhibited a more stable signal output and could detect small strain movements such as swallowing and frowning. Zigzag hydrogel sensors were expected to provide a new strategy for the development of highly sensitive, stable and reliable sensing systems for electronic skin sensors and soft robots.