The invention discloses an alternating current bus voltage regulation method based on reactive power control of a flexible direct current converter valve. The voltage regulation principle of a parallel capacitor is used to calculate the flexible direct current transmission reactive power voltage regulation. A test step is used to calculate reactive power finally sent out, and two-step method is used to calculate to realize quantitative calculation of the flexible direct current reactive power for alternating current voltage. The method is simple and practical, does not rely on complex calculations, does not need to consider the converter station operation mode, identifies the sent reactive power reference value, and prevents a system from the disturbance of frequent adjustment. The risk of field operations is reduced.