The utility model relates to a hand-held circuit breaker open-phase time tester comprises a display portion, an operation circuit, a sampling circuit, a decoder and a power supply. The sampling circuit is in contact with a circuit breaker and acquires two paths of signals of the circuit breaker. An encoder is used for converting the signals, and then the converted signals are displayed through a display. The signals acquired by the acquisition circuit are sent to an XOR gate to be subjected to processing through a reverser, and reversal is realized through the reverser. The signals are then sent to a double-D trigger of the operation circuit. A first contact point triggers synchronization and a counter begins to carry out statistical counting on a crystal oscillator. When a second contact point is in contact with the ground, the counter is triggered to stop counting, and displaying is carried out on a nixie tube through the decoder. The advantages are that by means of detecting a frequency difference triggered by the first contact point and the second contact point, a trigger time difference is obtained through the operation circuit and the decoder, and the open-phase time of the circuit breaker is further obtained. The hand-held circuit breaker open-phase time tester is high in integration level, small in occupied space, convenient to carry, simple in structure and convenient to operate.