According to the requirements for marine profiles cold bending production of small and medium shipyards，the ribs’ type value data were used to generate the approximate arc cubic parameter spline function and curve based on accumulative string length by computer programs. On the basis of the parameter spline curve, a kind of arc angle measurement control method was put forward.Using this measurement control method, the large measurement mechanism needed in previous control methods was avoided. Then, copper wire was used to simulate neutral layers of the profiles’ curves, and the simulant experiments research was made in the experimental devices. Proper fulcrum distance and feed distance were adopted to verify this measurement control method. The experimental results prove the method’〖KG-*2〗s rationality and practicability. Based on the arc angle measurement control method, CNC marine profiles cold bending equipment can be developed, by which the manufacturing level and production efficiency of shipyards will be greatly improved, and great economic benefit and social benefit would be produced.