In signal processing of vibration and noise, It is inefficient and difficult to extract data from the image containing complex curves in traditional method, and affects data analysis. In order to solve this problem, The paper combines the continuity of curve, the spatial characteristic between complex curves and the characteristic of RGB model, An algorithm aimed at identification and extraction of two curves and an algorithm aimed at identification and extraction of color multicurve were proposed, through recognizing, extracting, storing the coordinate data of each curve, and interpolating each curve, the simulation achieved data extraction of complex curve image. The proposed algorithms can quickly obtain the accurate result of curve image processing, and provided a reference for analysing and processing complex curve data of the image.