The invention discloses a tunnel strengthening treatment method and a support structure based on the positions of dissolving cavities. The tunnel strengthening treatment method includes the following steps that firstly, the nearest distance L between the dissolving cavities and a tunnel is determined; secondly, the safety thickness H of a karst region of the tunnel is determined; thirdly, the safety of the tunnel affected by the dissolving cavities of the karst region is judged; and fourthly, different tunnel support structures are adopted according to the safety of the tunnel. The tunnel strengthening treatment method and the support structure based on the positions of the dissolving cavities have the following beneficial effects that firstly, a calculation method is reasonable, consideration is comprehensive, design is reasonable, the construction speed is high, the use effect is good, and different support methods and structures are adopted according to the different safety conditions of the tunnel; and secondly, the corresponding support structures are selected according to the positions of the dissolving cavities, and the construction and safety operation problems of passing of the part, in the karst region, of the tunnel can be effectively solved.