The processing method for repairing a blade tip mechanism of a wind turbine generator set. The processing method includes the following steps: dismantling parts inside a blade tip and a guiding box; welding a bolt at the deformation zone of a back plate of the guiding box, installing a back plate correction tool at the edge of the guiding box, the bolt penetrates through the back plate correction tool and is connected with a nut, carrying out correction on the back plate of the guiding box by screwing the nut, after the correction is finished, welding the back plate and a base, and dismantling the back plate correction tool and the bolt; welding the bolt at the deformation zone of a side plate of the guiding, installing a side plate correction tool inside the guiding box, the bolt penetrates through the side plate correction tool and is connected with a nut, and carrying out correction on the side plate of the guiding box by screwing the nut, after the correction is finished, welding the side plate, the back plate and the base, and dismantling the side plate correction tool and the bolt. According to the processing method for repairing the blade tip mechanism of the wind turbine generator set, correction and welding to deformation and open weld of the guiding box of vane blade tip braking mechanism of a fixing blade wind turbine generator set are carried out, and spare parts do not need to be replaced to solve stoppage of the blade tip braking mechanism. According to the process method for repairing the blade tip mechanism of the wind turbine generator set, the technology is simple, and maintenance cost is low.