Abstract: The SPC-II fish robot prototype is an experimental platform which validates the stability, high efficiency and maneuverability by utilizing the caudal fin propulsion mechanism. SPC-II doesn't simply mimic the shape of certainkind of real fish, but takes the swimming stability as the primary factor of undersea bionic vehicle design that is taken into consideration. It overcome the swing of fish body effectively ,which makes tail fin propulsion break away from disturbance and reduce the sailing resistance. The SPC-II, about 1.2 m long, utilizes an entirely rigid pressure hull with batteries, GPS(global position system), compass and two-joint servomotors installed inside. SPC-II can swim freely at a fixed depth within 5 m under water. Its maximum speed is 2.8 kn and its power consumption is less than 250 W.The line sailing velocity and turning maneuverability were tested. The test under the badly circumstance of long distance was taken. The comparisons with experimental platform home and broad show that he SPC-II fish has its own advantages in the terms of its shape and sailing velocity.