The utility model discloses a photovoltaic grid-connected control device, and the device comprises a microcontroller module, a relay protection circuit, and a communication interface circuit. The input end of the microcontroller module is connected with a grid-connected switching circuit, a first A/D sampling circuit for collecting the parameters of a commercial power voltage, a first voltage zero-cross detection circuit, a second A/D sampling circuit for collecting the parameters of a photovoltaic inversion AC voltage, and a second voltage zero-cross detection circuit. The output end of the microcontroller module is connected with a display and a signal amplification circuit. The output end of the signal amplification circuit is connected with a grid-connected mode switching circuit, and the output end of the grid-connected mode switching circuit is connected with the input end of the relay protection circuit. The device is novel in design, is simple in structure, is high in collection precision of grid-connected data, can select flexibly a mode of automatic grid connection or manual grid connection, prevents problems of misjudgment and system short circuit and a problem that a circuit breaker cannot be separated normally from causing serious consequences, and is high in practicality.