In this paper, to deal with the locomotion in underwater environment, we designed a novel type of leg, inspired by stick insect legs. The biomimetic leg is composed of two segments of ICPF (ionic conducting polymer film) actuators with a 2-DOF motion. It has simple structure, simple control method, and good localization characteristic. We designed and developed a prototype microrobot with 3 units of the legs. The dimension of the microrobot is 48*20*17 mm3 and its dried weight is 0.65 g. We have measured the speeds with different control signals. The experimental results show that it can arrive at a speed of 4.7 mm/s with a control signal of 5 Hz and 10 V. And results indicate that the novel type leg has a good speed performance and localization in aquatic environment. The microrobot using ICPF actuators has powerful applications in the biomedical and naval fields