A method for detecting a thickness of bonded rubber of a carbon black in a natural rubber based for reinforcement performance is provided. An ultra-thin frozen microtome to prepare a sample, a tapping mode of the atomic force microscope is used, and when characterizes the carbon black and rubber composite material, the difference of imaging characteristics between morphological and phase diagrams is used, the characteristics of bonded rubber of carbon black reinforced composite material can be observed to obtain the thickness of bonded rubber, and then influence of bonded rubber on rubber performance and the reinforcement performance of the carbon black in the rubber are analyzed. The method has advantages of simple operation, no need for excessive sample processing, high detection efficiency, clear detection images and high detection accuracy, thereby having better applicability and providing a new method and idea for studying reinforcements of fillers.