The invention discloses a safety anti-falling device for rotor operation of a hydro-generator. The device is composed of a circular base plate, a rotatable stand column, a quincunx-shaped multi-hanging-point safety belt hanging disc and three fixing bolts, wherein the diameter of the circular base plate is larger than that of a center hole of a hydro-generator rotor. When in use, the safety anti-falling device can be installed at the center position of the upper end of the hydro-generator rotor through the cooperation between the three fixing bolts and an upper end shaft connecting bolt hole formed in an original upper end shaft mounting flange plate on the hydro-generator rotor, so that the center hole of the hydro-generator rotor is blocked, and the situation that personnel, machine parts and tools accidentally fall into the center hole of the hydro-generator rotor during maintenance can be prevented, and meanwhile multiple standard safety belt hanging points are provided for maintenance personnel who work at the upper end of the hydro-generator rotor, so that the personal safety of the maintenance personnel is ensured; and in addition, the multiple safety belt hanging points aredesigned, so that the safety anti-falling device can meet the requirement of simultaneous use for multiple maintenance personnel at the upper end of the hydro-generator rotor, and thus is suitable for a working condition where the multiple maintenance personnel should work collaboratively during the maintenance of the hydro-generator rotor.