Recently, ionic actuator as a kind of artificial muscle has attracted great attentions according to their remarkable strain under low-voltage stimulation. Here, we investigated a biocompatible ionic polymer actuator, which consists of multi-walled carbon nanotubes (MCNTs) film as the double electrode layer and an electrolyte layer equipped with a chitosan polymer skeleton. As a result, we found it presented various electromechanical properties under the preparation factors of the different additive glycerol (0mL, 2mL, 4mL). The actuators with 2mL glycerol behaved a longer life bending (65 times), which was obviously surpassed by the others. Also, based on strain and stress testing, Young's modulus of the electrolyte presented a decreasing trend. In fact, the improvement was mainly due to the weakened inter-molecular hydrogen and the rotation molecular of the electrolyte film. Results show the additive inside the electrolyte is very effective to improve the performance of artificial muscle.