Embodiments of the invention provide a frequency conversion control method and device. The method comprises the steps of acquiring a three-phase voltage of an electrical apparatus, and performing two-phase rotation coordinate orthogonal decomposition on the three-phase voltage to obtain a first input voltage and a second input voltage; based on the first input voltage and according to a preset aggregation prediction control rule, determining a first control voltage increment, and based on the second input voltage and according to a preset regulation control rule, determining a second control voltage increment; performing coordinate conversion and synthesis on the first control voltage increment and the second control voltage increment to obtain a three-phase control voltage; sending a control instruction used for indicating generation of the three-phase control voltage to a frequency converter. The method and the device reduce computation complexity, save computation time, prevent error caused by inaccurate model parameters and improve the stability and accuracy of frequency converters.