The invention discloses a control device and a control method for a bucket opening mechanism of a mining excavator. The control device comprises a first measuring module, a second measuring module, athird measuring module and a control module; the first measuring module is installed on a pushing and pressing speed reducer of the mining excavator, the second measuring module is installed on a lifting speed reducer of the mining excavator, the third measuring module is installed on a bucket opening motor of the mining excavator, the control module is connected with the first measuring module, the second measuring module, the third measuring module and the bucket opening motor, and the control module controls and adjusts the rotating speed and output torque of the bucket opening motor. According to the control device and the control method for the bucket opening mechanism of the mining excavator, the deflection of the bucket opening steel wire rope can be ensured, and the shaking interference of the bucket opening steel wire rope is avoided; and meanwhile, when a bucket rod approaches the position of the bucket opening, the bucket opening motor is controlled to enable the large-torque output mode, so that the bucket opening time can be effectively reduced, the bucket opening efficiency is improved, and the cycle period is shortened.