Research Conclusions: The karsts encountered in the construction can be divided into four types according to the engineering-geological, characteristics, namely cave type, fluid bowl type, pipe type and large-sized karsts, and they can be divided further according to the hydro-geological characteristics, namely free filling type, semi-filling type, filling type, flow type, overflow type and underground river type. For the kasrst cave, the reinforcing measures of filling, refilling and grouting can be taken, for fluid bowl, the reinforcing measures of filling guard arch, supporting the excavated area and grouting can be taken , for the karst pipe, the reinforcing measures of filling guard arch, drainage in advance, grouting; support with large pipe shed and remaining the existing drainage system can be taken, and for large-sized karst; the reinforcing measures of filling guard arch; grouting and support with large pipe shed can be taken for the upper and steel pipe pile, slab and beam crossing the tunnel; cap of pile trestle and filling subgrade can be taken for the bottom.