The loading chamber of main shaft skip was damaged seriously in Majialiang coalmine and the supporting strength was insufficient. By the analysis on the damage reasons, new reinforced scheme of large diameter pre-stressed grouting cable anchor was proposed and the paper introduces the key points of the design and construction technology. The numerical simulations and the industrial test showed that the scheme can meet the requirements of the force and deformation of the loading chamber， the cable force is reasonable, the roof and 2 sides of displacement are effectively controlled with good reinforcing effect.