Vertical deep hole prsplitting blasting has been widely used in subgrade cutting and mining, however, due to the big muck pieces and the unsmooth floor, it has been little used in the construction of large underground caverns. A new blasting method, which combines the vertical deep hole presplitting blasting and horizontal hole smooth blasting, is proposed for the construction of a large underground cavern on basis of horizontal hole smooth blasting technology and rational blasting parameters, so as to speed up the construction and reduce the construction costs. In the paper, the diameter, length, spacing, charging and stemming of the blasting holes are presented. The blasting practice shows that, due to the application of the new technologies presented above, the problem of big muck pieces and unsmooth floor has been solved, the construction efficiency has been improved and good effect has been achieved. The paper can provide reference for other similar projects in the future. 