The invention discloses a power-distribution workshop busbar power-frequency magnetic field calculating method. The initial position, width and spacing value of each busbar in the power-distribution workshop are obtained and input to a data processing unit through an input unit; a power-frequency magnetic field calculating model is established; the single-phase magnetic field intensity of spatial points around a single-phase busbar is calculated; in dependence on the single-phase magnetic field intensity, the whole magnetic field intensity formed by three phase busbars in space is calculated by means of a superposition principle; and the initial position, width and spacing value of each busbar and the corresponding whole magnetic field intensity are stored in a storage cell according to a corresponding relation. In dependence on the relation between the magnetic induction intensity and the current, the magnetic field change condition of busbars with different lengths and different spacing values in each position of the space is analyzed, and the relation between each parameter and the magnetic field intensity is finally obtained. The power-distribution workshop busbar power-frequency magnetic field calculating method can be applied to the design of the power-distribution workshop busbar power-frequency magnetic field shielding scheme.