The invention discloses a digital body-building system which comprises a video acquisition module, a motion state acquisition module, a vital sign acquisition module, a data processing module, an action standard judgment module, an action guidance advice output module, an action command recognition module, a central processing unit, a three-dimensional teaching module, a man-machine operation module, a body-building result statistics module, a physical model building module, a virtual actuator, a virtual sensor and a simulation analysis module. The digital body-building system disclosed by the invention realizes automatic determination and guidance of body-building actions; by using the delivery function of a three-dimensional teaching video of the system, the repeated playback and learning of the teaching video or a guidance video can be performed, so that repeated viewing and understanding of body builders for each action are greatly facilitated, the body-building efficiency is improved, the actions are more standard, and the workload of teachers is also reduced; meanwhile, the comprehensive analysis on human body situations and the targeted body-building program planning can also be realized in a manner of combining a physical model and simulated analysis according to the situations of each body builder.