The invention discloses a method for eliminating variable-frequency vibration point of a motor on a DCS. An upper and lower limit alarming module, NON modules, AND modules, an upper limit determination module, a constant module, and a switching module in the DCS are used for forming a vibration point elimination algorithm. The vibration point elimination algorithm is configured to be formed by self-defined functional modules for invoking; and each vibration point corresponds to one self-defined functional module. The vibration points and the vibration zones are set by using the self-defined functional modules; and head-tail series connection is carried out on inputs and outputs of the corresponding self-defined functional modules to realize elimination of variable-frequency vibration points of the motor, so that the variable-frequency output instruction of the motor avoids the vibration zones. According to the method disclosed by the invention, configuration is carried out by using theown basic function blocks of the DCS system and the algorithm enabling the variable-frequency output instruction to avoid the vibration zones during the operation process is searched, so that the frequency converter works stably, safely and reliably.