The invention relates to a system and a method for collecting data of a power transmission and transformation project. The system comprises a data acquisition module, a data processing module, a display and keyboard module and a data communication module, and is characterized in that the data acquisition module acquires signals in a timing mode, carries out AD conversion and outputs converted data; the data processing module carries out processing and analysis on the converted data, and uploads the data to an upper computer; the display and keyboard module displays relevant information of various electric power parameters and harmonic waves through an LCD screen, and processes command information inputted by a user through a keyboard; and the data communication module is responsible for processing data transmitted through a communication line, performs data communication with the upper computer, and uploads waveform data and a calculation result. The beneficial effects are that a modular design method is adopted, that is, software is divided into a plurality of modules according to functions of the whole device, then program designing and debugging are carried out according to each function module in the system, and finally, the modules are connected so as to carry out overall debugging, thereby being not only simple and clear in structure, but also being conducive to function expansion and transplantation and modification of programs.