In order to isolate the influx of water from adjacent coal mines, combined with the original waterproof gate wall layout and surrounding rock characteristics of the main coking coal mine, two waterproof gate wall reinforcement construction schemes are proposed, and the stress distribution and displacement deformation of the two waterproof gate walls are analyzed by numerical simulation. Optimized the construction plan from the perspectives of history, construction safety, and cost control, and decided to adopt the plan of strengthening the construction of the new gate wall based on the original gate wall and forming a new whole with the original gate wall. The key points and construction techniques of reinforcement construction are put forward, which avoids the cost of dismantling the original gate wall and the problems of surrounding rock damage. Field application practice shows that the reinforcement effect of the waterproof gate wall is obvious, which effectively isolates the influx of old empty water from adjacent mines, and provides a reference for the waterproof gate wall reinforcement construction under similar conditions.