Based on technical requirements of PIV (Particle Image Velocimetry) system, experiment setup of submerged water jet flow was founded and dynamic characteristics of it were studied. The experiments proved the feasibility of advanced PIV technology for dynamic characteristics and velocity structure research. The experiments show that the axial velocity distribution on the jet flow section keeps the self- resemblance, and the self stimulated curve is got; time average velocity distribution inside of the jet flow is uniform, which is attenuation along the shot; axial velocity on the boundary is fluctuated by effect of around liquid.