In the previous study, a self-propelled two-joint dolphin robot to study propulsive mechanisms of high-speed swimming animals was constructed. The total body length of the robot is 1887mm, which is similar to the length of actual fast swimming animals. The robot is composed of a streamlined body and a rectangular caudal fin. The first joint is actuated by a starter motor which has the maximum output power of 7.4kW. The second joint is moved passively by springs. In this report, the swimming motion of the dolphin robot in the absolute space was measured by using a three-dimensional motion analysis system. The results of the motion measurement was introduced into our simulation program of the three-dimensional panel method. The simulation results of the propulsive efficiency exhibit same tendency as the experimental ones, although the simulation results becomes 10∿20% higher than the experimental ones.