Abstract: An S-lay crane barge, named CNOOC 201, has been built for pipe laying in deepwater oil/gas fields in the South China Sea. It is due to be commissioned by the end of the year 2010. A special lifting system is developed to meet the challenge that installing deepwater risers from an S-lay barge is difficult and has not been achieved. The purpose of this paper was to investigate the model test on such an innovative system, which has to be done before field application. By applying the similarity theory, the movement of the S-lay barge is simulated through a six degrees-of-freedom motion platform, and a truncated model riser is utilized for the model testing. The displacement and force boundary conditions at the truncated position of the riser are obtained from the catenary governing equation and become realized by a slideway cart and a loading system designed to control the configuration of the model riser, which presents a similar configuration to a real riser in deepwater. The test results are in very good agreement with theoretical calculations, showing that the active truncated test is applicable for controlling the configuration of the deepwater riser in model testing investigation.