The invention discloses a cascaded cross-scale tool servo device and a high-frequency control method thereof. The device comprises a flexible device platform, a first piezoelectric stack, a second piezoelectric stack, a first capacitive displacement sensor, a second capacitive displacement sensor, a diamond cutter, straight circular flexible hinges and straight plate type flexible hinges. The diamond tool is located at the front end of the middle of the flexible device platform, the first piezoelectric stack is located on the lower portion of the diamond tool, the straight plate type flexiblehinges are located on the two sides of the first piezoelectric stack driving block, the second piezoelectric stack is located on the lower portion of the first piezoelectric stack, and the straight circular type flexible hinges are located on the two sides of the second piezoelectric stack driving block. According to the cross-scale rapid tool servo system based on cascade driving of two piezoelectric stacks and guiding of the flexible mechanism, the primary driving stroke is large, the bandwidth is low, the secondary driving stroke is small, the bandwidth is high, and the requirements of complex microstructure cutting for large-stroke, high-bandwidth and high-precision tool path tracking can be effectively met through combination of the primary driving stroke and the secondary driving stroke.