The invention belongs to the technical field of granular system power transmission chain identification, and relates to a method for identifying a granular system power transmission chain. The method includes the steps that firstly, a granular system is loaded, and granular system images before and after deformation are collected to be used as an original image and a target image respectively; then, the original image and the target image are analyzed, and after a displacement field and a strain field in the granular system surface of the target image at the corresponding moment are obtained, the stress of each point is obtained according to the strain of each point in the strain field; afterwards, image edge detection is conducted on the target image, granular centroids are identified, the coordinates of the granular centroids and the position coordinates of contact points of all granules are read, a force equilibrium and torque equilibrium equation is established for each granule, and the size and orientation of contact force at different contact points on all the granules are acquired through calculation; at last, the contact force of each granule is drawn, and the graph which is continuously represented by the contact force between adjacent granules is the path of the power transmission chain. The method is simple, scientific in principle, convenient and flexible to use, high in practicability, large in development prospect and wide in applied range.