The invention relates to a method for comprehensively treating the ecological environment of a coal gangue hill, which belongs to the field of mineral waste treatment and ecological environment restoration. The method mainly solves the problems of fire extinction, fire prevention and vegetation construction of the coal gangue hill. The method comprises the steps: the on-site reconnaissance of the coal gangue hill is carried out, and a construction operation plan is established; with fire prevention as principal and the combination of fire prevention and fire extinction, the fire prevention is crucial and is combined with the fire extinction, a thin layer of slurry is firstly sprayed on the coal gangue hill by a mechanical method to completely seal to form a sealing layer (8), transition slurry is sprayed on the sealing layer (8) to completely cover the sealing layer (8) to form a transition layer (9), slurry containing grass-shrub vegetation is spayed on the transition layer (9) to completely cover the transition layer (9) to form a planting layer (10); the contour line girdle band type operation in the spraying process is carried out from bottom to top to gradually and completely cover the hill, and different operating modes are selected according to practical conditions. The invention can not disturb the structure of the coal gangue hill, takes the fire prevention as the principal, combines the fire prevention with the fire extinction, has good and durable fire prevention effect, uses reliable and effective fire prevention and fire extinction measures as guarantee conditions to construct the planting layer, adopts grass-shrub plants, carries out hill sealing management and ensures vegetation restoration; in addition, the method uses the prior specialized mechanical devices to carry out construction operation, is easy to implement, has little difficulty, high efficiency and low investment and can ensure treatment effect.