The invention provides a dynamic loading method of a program module. The method comprises the steps that 1, a compiling system is provided and is used for compiling a program source code into a program module which can be dynamically loaded, and the program module comprises a binary system code segment and a data segment; 2, a dynamic loader is provided, and comprises an installation module which is used for installing the program module into a memory space of the program module and a loading module which is used for loading the program module into a runtime data storage space in running; 3, the binary system code segment of the program module calculates a global variable address in the program source code through a data segment base address mapping table of the program module in the runtime data storage space; 4, a global variable corresponding to the global variable address is read and written and referenced. According to the dynamic loading method, the operation, namely back-up, erasure and merging writing, on the memory space in repositioning can be avoided, and the dynamic loading efficiency is improved.