The invention discloses a fast thyristor adjustment device and method compatible with voltage adjustment and reactive power compensation. The device comprises an autotransformer, and bidirectional thyristors T3 and T4 for adjusting gears, wherein the autotransformer is formed by combining a series transformer B1, a compensation capacitor C, windings B2, B3, B4 and bidirectional thyristors T1 and T2. Voltage and reactive power integrated adjustment can be achieved, so that (1) automatic keeping of output voltage within a change range from -3% to +3% when user terminal voltage is in a change range from 0% to +10% can be achieved; and (2) reactive power of a circuit can be automatically compensated according to a voltage adjustment increment, the adjustment time can be controlled at millisecond level through adjusting the gear through the thyristors, and the fast thyristor adjustment device and method are especially suitable for applications with a large load fluctuation and a relatively large reactive power gap ratio.