The data from small vessels turning circle were used to analyze the scale of the turning circle in the original Chinese code.In order to verify whether the provisions of the code is available for the large vessel’s turning around,we carry out a large number of full-scale large vessel observation tests in many typical ports in China，and obtain the sample data of 57 large vessels’ turning circles.Based on the statistical analysis of these data,we get some regularity conclusions about the turning circle of the large vessel,which provides a technical support for the revision of the codes.