The invention discloses a balancing ring automatic filling machine. The balancing ring automatic filling machine comprises an automatic control system, a rotating disc type working table, a gas measuring device, a salt water filling device, an opening sealing device and a weighing device, wherein the automatic control system is used for automatically controlling the whole automatic filling machine; the rotating disc type working table is used for achieving positioning and transposition of integrated operation of gas measuring, filling, opening sealing and checking procedures on balancing rings; the rotating disc type working table is provided with a plurality of working positions; the gas measuring device is used for conducting gas measuring on the balancing rings to be filled; the salt water filling device is used for achieving salt water filling on the balancing rings in sequence by several times; the opening sealing device is used for achieving sealing and plugging on a filling opening in the balancing ring; and the weighing device is used for achieving test of the weight of the balancing ring after and before filling and checking whether the weight of the balancing ring meets requirements of filling or not. The invention further discloses the filling method. According to the balancing ring automatic filling machine and the filling method, the degree of automation is high, synchronous automatic operation is achieved, gradual filling by several times is adopted, it can be effectively ensured that salt water in the balancing ring does not backwashed and overflows, the service life of equipment is long, operation is precise, and the quality is high.