The invention provides an intelligent miniature circuit breaker synchronism testing method, including closing synchronism testing and comprising the steps of: S01, performing parallel shorted connection of input ends of all electrodes of a circuit breaker and connecting a power source L wire therein; S02, manually pushing an operating handle of the circuit breaker to switch on the circuit breaker and recording the power obtaining time of each output end of the circuit breaker; S03, using the difference between the maximum power obtaining time and the minimum power obtaining time of the output ends of the circuit breaker as the closing synchronism time, and judging that the circuit breaker is qualified if the closing synchronism time is less than the standard closing synchronism time and the circuit breaker is non-qualified otherwise. The testing method can improve the closing reliability of circuit breakers. The invention also provides an intelligent miniature circuit breaker synchronism testing device comprising a power source unit and a time testing unit, wherein the L electrode of the power source unit is connected to an input end of a circuit breaker and an input end of the time testing unit is connected with an output end of the circuit breaker. The testing device is simple in structure and simple to operate.