The invention discloses a closed type drilled and steel bar-planted reinforced structure which comprises a structure to be reinforced, wherein at least one circle of closed type anchoring hole is formed in the structure to be reinforced; steel bar bundles are mounted in the anchoring holes; and concrete is further cast between the anchoring holes and the steel bar bundles. A reinforcing method comprises the following steps: during reinforcing, calculating and determining the number of circles of the closed type anchoring holes, the distribution positions of the anchoring holes, the number of holes and the depths of the holes according to stress, then drilling to obtain the anchoring holes, and cleaning and blowing the interiors of the anchoring holes to dry; calculating and determining the diameters and the lengths of steel bars in the steel bar bundles according to the stress, binding the steel bars, and hoisting and fixing the steel bar bundles to the centers in the anchoring holes; and finally casting the concrete to obtain the closed type drilled and steel bar-planted reinforced structure. The reinforced structure provided by the invention is economic in figure, safe and reliable; and the reinforcing method is easy to operate and lower in cost, and has better economic benefits.