The utility model relates to a gob-side entry retaining Z-shaped ventilation system of a coal face. A coal face intake airway and a coal face return airway are positioned on the front and rear sides of a coal face respectively and are arranged at an angle of 90 degrees with the coal face to form the Z-shaped ventilation system of the coal face. The coal face return airway is retained by using a pier stud material, a flexible formwork and a high-water material in a gob-side entry retaining mode on the coal face; after the mining of a previous coal face is finished, the coal face can be reused as a part of the intake airway of a next coal face, collar pillars are not required to be arranged between two adjacent coal faces for isolation, and a mining roadway or the mining return airway can be reused during arrangement of adjacent mining areas. According to the system, the roadway tunneling during arrangement of the coal face of a coal mine can be effectively reduced, the coal recovery rate can be improved, and high yield and high efficiency of the coal mine are realized.