The invention relates to the technical field of galvanized plates, in particular to a production process of a spangle-free hot galvanized plate with an ultra-thick zinc layer of 0.9-2.5 mm. The production process comprises an ESP process and a PGL acid galvanizing process; specifically, the smelting components of a hot rolled steel strip produced by the ESP process comprise C: less than or equal to 0.12%, Si: less than or equal to 0.50%, Mn: less than or equal to 0.60%, P: less than or equal to 0.10%, S: less than or equal to 0.045%, and the balance Fe; a casting blank is directly subjected tohot rolling without being heated by a soaking pit; and the PGL acid galvanizing process comprises acid washing, leveling, galvanizing, finishing, passivating and coiling into a hot galvanized coil. According to the production process, the spangle-free hot galvanized plate with the ultra-thick zinc layer with the thickness of 0.9-2.5 mm and the weight of 660 g/m<2> can be produced, the surface quality of the product is good, the size precision is high, the bonding force of the zinc layer is strong, and the performance is stable.