Chitosan (CS) is a natural material with remarkable biocompatibility, biodegradability, and electron-donating ability, making it an excellent candidate for use in triboelectric nanogenerators (TENGs) for the development of wearable sensors. The output performance of CS has been improved by modifications with fillers or functional groups. However, it is still difficult to realize excellent power generation and desired degradation simultaneously. Herein, we design a CS friction layer by plasticizer addition and a template method to obtain a high–performance and fully degradable TENG–based sensor for effective information transmission. Because of the microstructure design of the friction film and glycerol plasticizer addition, the CS–glycerol friction layer has a high contact area in the friction process. Therefore, this CS–glycerol TENG achieves a higher output performance with an open–circuit voltage of 127   V, 2.32 times higher than that of a CS–based TENG fabricated without a template method. Finally, the CS–glycerol TENG sensor is used in an alphabetic code transfer application and can be completely degraded in the soil within 69 days after completing its working cycle. The template and plasticizer strategy effectively improves the CS based TENG output performance and maintains the complete degradation. Furthermore, because of the extensibility, positive cooling ability, and antibacterial activity, the degradable CS–glycerol TENG sensor has great potential for application in multifunctional wearable sensors, especially for disposable medical products.