Thread angle identification is a common method to distinguish thread types. Traditional detection methods have many disadvantages such as low efficiency and high cost and gauges are easy to be abraded. The needs of high efficient development of modern industry are not met any more. CCD is used to obtain the basic image of thread. And the thread contour is analyzed through image smoothness, edge detection, binary image production and contour hunting. The thread angle parameters are measured and identified. The measurement methods of thread angle parameter using machine vision are discussed. And a thread recognition system mainly based on the machine vision recognition technology and integrated visual sensing with image processing system is designed. The feasibility and correctness of the method is proved from theory and practice.