The invention discloses an all-dimensional cleaning device for on-line monitoring water quality sensors in aquaculture. An installation rack drive motor is connected to the center of an installation rack through an output shaft of the installation rack drive motor and is connected to a controller; the water quality sensors of an even number are installed above the installation rack in the peripheral direction with the axis of the output shaft of the installation rack drive motor as the center; a side surface brush driven by a side surface brush drive motor and a bottom surface brush driven by a bottom surface brush drive motor are symmetrically installed at the positions, on the left side and the right side of the output shaft of the installation rack drive motor, of the upper part of the installation rack. According to the device, the installation rack rotates so that the side surface brush and the bottom surface brush can sequentially clean the multiple sensors, the sampling accuracy can be guaranteed, and the utilization rate of the cleaning device is increased; the controller controls automatic switching between water quality monitoring and sensor cleaning, manual operation is reduced, and the system work efficiency is improved.