The invention relates to an automatic addressing data acquisition system and method thereof. A collector comprises a main module and a plurality of extension modules. The extension modules are responsible for acquisition of sensor data, and the main module is responsible for achieving the functions of automatic data processing, storage, communication and the like; the main module and the extension modules are in physical connection through extension cables, the extension cables serve as power supply buses of the extension modules and also serve as communication buses for interaction data of the extension modules and the main module, and after power-on initialization of the extension modules is finished, address allocation is automatically achieved through the communication buses. Compared with an acquisition system in the prior art, the novel sensor data acquisition system overcomes the defect that each time an extension module is added, programming personnel need to remember the number and information of the module and set parameters of the module on site, overcomes the defect that an original address is prone to being confusing when the module is repaired, maintained or replaced, and has high economic benefits.