The invention relates to a bidirectional eccentric loading device for bamboo bending members, and an installation method. The device comprises two steel cylinder sleeves which are in vertical mirror symmetry, two ball hinged seats, and the bamboo bending members. The steel cylinder sleeves are disposed on the ball hinged seats, and the bamboo bending members are inserted into hollow steel cylinders in the steel cylinder sleeves. The device is advantageous in that 1), the structure is simple and is easy to install, the main body of the loading device only comprises the steel cylinder sleeves and the ball hinged seats, and the installation step is easy; 2), the device is clear in force transmission and is good in integrity, the steel cylinder sleeves can serve as attached corbels fixed at two ends of the member so as to enlarge the force bearing range of an end face, and the ball hinged seats achieve the hinging of the members; 3), the eccentric position is flexible and controllable, ball hinges and the steel cylinder sleeves are connected through holding-on teeth, and the movable ball hinges change the relative position of the steel cylinder sleeves and the ball hinges, thereby achieving the design of different eccentric distances easily; 4), the device is high in popularity, a bamboo member in any rectangular shape can be connected with the device through a steel filling piece and a reserved bolt hole, and the device can be used for carrying out the bidirectional eccentric bearing test of many types of bamboo materials.