A hot dipped high manganese steel and a manufacturing method therefor. The high manganese steel comprises a steel base plate and a coating on the surface of the steel base plate. The core of the steel base plate is austenite. The surface layer of the steel base plate is a ferrite fine grain layer. The ferrite fine grain layer comprises an oxide of Al. Furthermore, the steel base plate of the hot dipped high manganese steel comprises, in mass percentages, 10 to 30% of Mn element, 1 to 2% of Al element, and 0.4 to 0.8% of C element. The manufacturing method comprises: 1) manufacturing strip steel; 2) primary annealing and acid washing; 3) secondary annealing and hot dipping.