Chitosan adhesive hydrogels have attracted interest because of their unique properties. However, it is still a challenge to use simple and unmodified chitosan to synthesize multifunctional hydrogels with adhesive, self-healing and strain sensing properties. Here, a multifunctional hydrogel of Ca²⁺-chitosan/polyacrylamide（Ca²⁺- CS/PAAm）with adhesive self-healing and strain sensing properties was carried out by one-step preparation method. The hydrogel has the ability to adhere to a variety of materials, wherein the adhesion strength to rubber surface is 48.4 kPa. The hydrogel has excellent strain sensing capability on finger bending or cyclic stretching, the sensitivity factor is 0.41 ± 0.015. The cut hydrogel healed completely at room temperature within 4 h, and the healing hydrogel can be stretched to 5 times of its original length. This makes Ca²⁺-CS/PAAm hydrogel to be great potential in the application of strain sensors, wound dressing and skin adhesives.