The invention discloses a process for constructing an impervious concrete wall by using an open excavation and inverted construction method. The process comprises the steps of constructing guide grooves and a construction platform, segmentally constructing lining walls from top to bottom and pouring an impervious wall from bottom to top. The process is adapted to the perpendicular open excavation of an ultra-long, ultra-deep and large-section impervious wall structure; compared with those of an impervious concrete wall constructed by a conventional method, groove holes constructed by an open excavation and inverted construction grooving process have the advantage that high-flow regime concrete has better compaction effects on the lining walls and soil bodies on the two sides, so that the stress relaxation conditions of the soil bodies on the two sides are changed, and changes in the permeation boundary conditions of the impervious concrete wall are small; the impervious concrete wall constructed by the open excavation and inverted construction method has tangible construction quality, and procedure and process control is ensured, so that the problems of high hole collapse rate and low grooving efficiency of the groove holes during the construction of a loose sandy gravel layer impervious concrete wall are solved, and the joint quality of the impervious concrete wall is ensured.