Dynamic analysis of a Near Surface Disconnectable Drilling Riser (NSDDR) which has an air can system near the top to make free-standing condition was carried out by means of 2 calculation codes : one is based on FEM, and the other Ohkusu's method (1990). To obtain the verification data, tank tests were conducted using a riser model with about 16.7m in length corresponding to 750m in fullscale. As a result of the comparisons, we found that 2 codes can predict accurately the behavior, bending moment, tension and inclination for connected, hanging and free-standing risers, and the bending moment acting on the free-standing riser in waves is consdierably small compared with the other riser modes.