Abstract: Cuttlefish is a common marine fish with good maneuverability for fast-moving mechanism during escape. This mechanism achieves jet propulsion through rapid contraction of the soft mantle. Ionic polymer metal composite（IPMC） is a flexible driving material with large deformation that is widely used in underwater bionic robots.It can simulate the shrinkage of the mantle film in the jet movement of cuttlefish through its flexible deformation. Therefore, based on the principle of cuttlefish jet propulsion, an imitating cuttlefish injection device is developed by using IPMC as actuator, which can realize underwater continuous jet propulsion. Firstly, the structure of the injection device was designed. Then, some structural parameters were optimized by simulation. Finally, the prototype was fabricated and tested for swimming performance. After swimming performance test, it is found that the average propulsion speed of the designed propulsion device is 1 mm/s, the instantaneous propulsion speed is 10 mm/s, the propulsion force is 0.782 mN, and the propulsion efficiency is 2.38%.The study of this device provides a new idea for the underwater driving mechanism of IPMC materials.