The utility model discloses a quick measuring system, which is used for carrying out quick measurement on capacitor groups on bridge arms of an H-bridge. The measuring system comprises a single-phase AC power supply, a first ammeter, a second ammeter, at least one adjustable capacitor group and a processor, wherein the single-phase AC power supply is used for providing power for both ends of the H-bridge; the first ammeter is used for measuring a main current value of the H-bridge; the second ammeter is used for measuring an unbalance current value of the H-bridge; the adjustable capacitor group is connected to capacitors of the capacitor groups in parallel; and the processor is connected with the first ammeter, the second ammeter and the adjustable capacitor group, and used for giving out control signals according to the main current value and the unbalance current value so as to carry out adjustment on the capacitance of the adjustable capacitor group. The processor adjusts the capacitance of the adjustable capacitor group according to the relation between the main current value and the unbalance current value, and can measure a deviation value of the capacitor groups on the bridge arms of the H-bridge quickly according to a variation law of the unbalance current value in the adjusting process.