The structured light image obtained when the line structured light is used for three dimensional measurement is susceptible to noise′s interference,which affects the accuracy of the center of the light stripe and limits the accuracy of the measurement system.In order to reduce the interference of random noise and improve the accuracy of light stripe center coordinate extraction,a light stripe center extraction method based on block matching is proposed.The skeleton thinning algorithm is used to initially extract the pixel center of the light stripe,generate image blocks around the center pixel contain the neighborhood information of each pixel center,then find the similar light stripe structures among the structured light image blocks through block matching,and use the similar structure to obtain the average value of the center coordinate of the light stripe as the final coordinates.Through simulation analysis and experimental analysis,the algorithm can effectively suppress the influence of image noise and improve the accuracy of light strip center extraction.