An independent suspension mechanism allowing upright jumping of back wheels of motor vehicles, and an auxiliary damping mechanism belong to the technical field of chassis of back wheels of motor vehicles having three or more wheels, which can solve the problem that back wheels of the motor vehicles of independent suspensions will change initial upright states thereof while performing upright jumping. The independent suspension mechanism can achieve the fact that the back wheels will not change the initial upright states thereof during upright jumping, can improve the relative load, can improve the driving stability, and has important significance. The technical keys include that a differential mechanism bridge and a main bearing bridge are fixedly connected; two ends of the differential mechanism are sleeved by back flat fork racks; damping devices are arranged between the back flat fork racks and the main bearing bridge; two ends of the differential mechanism bridge are locked with small chain wheels which are connected to big chain wheels arranged on the back flat fork racks through chains; and the auxiliary damping mechanism includes an upper +-shaped shaft rod assembly, an upper swing rod, a lower +-shaped shaft rod assembly, a lower swing rod, and damping devices.