The invention provides an underground impervious film connector and a construction method thereof. The underground impervious film connector comprises a connector body. Grouting grooves are respectively formed in two sides of the connector body. Fixed connecting portions are arranged in the grouting grooves. The grouting grooves and the fixed connecting portions stretch from the lateral end of theconnector body to the middle of the connector body. Openings are formed in two lateral ends of the connector body and communicate with the grouting grooves, and further the impervious film or permeable film can be stretched through the openings. Through winding of the fixed connecting portions, the impervious film or permeable film can be fixed. The aim of successful application of the imperviousfilm to underground seepage control construction is achieved. Construction quality and efficiency are further improved, and pollution caused by construction is reduced.