The invention discloses a single-fan virtual wind speed calculation method and system based on wind field wind speed association. The single-fan virtual wind speed calculation method at least comprises the steps of S1, carrying out data acquisition and storage, S2, carrying out data preprocessing, S3, carrying out associated fan selection, and S4, carrying out model training and storage: selecting associated historical data of an associated fan as an input value, inputting the input value into a learning model, and completing training of a wind speed fitting algorithm model; and S5, carrying out virtual wind speed calculation, calling the wind speed fitting algorithm model obtained through training in the step S4 in real time, and obtaining the current wind speed of a target wind turbine through fitting in combination with associated wind turbine associated data. According to the method, under the condition that an anemograph breaks down, auxiliary equipment does not need to be added, and the operation condition of the anemograph can be effectively judged and fitted. The method has the characteristics of simplicity and feasibility, can improve the phenomena of unit abnormity, unplanned shutdown and the like caused by anemograph faults, and improves the power generation efficiency of a unit.