The invention discloses a control device and method for a composite switch of a photovoltaic module. LORA wireless communication is adopted to collect the data of and monitor a photovoltaic module, and thus, active and passive shutdown of the voltage output of the photovoltaic module by a photovoltaic junction box is realized. A LORA wireless communication module sends the current, voltage, temperature and on-off state of the photovoltaic module up to a cloud platform. The cloud platform can issue a turn-off instruction to manually turn off the module, and the photovoltaic module turned off bythe instruction can only be opened through an instruction issued by the cloud platform. After the fault is removed or the cloud platform issues a turn-on instruction, a relay switch in the compositeswitch is closed first, and then, an MOSFET switch in the composite switch is closed. The spread of fire on the photovoltaic module is restrained, and the risk of fire is reduced. Moreover, a faulty photovoltaic module can be isolated, the risk of electric shock in fire detection is greatly reduced, and the production and power generation of other parts of the photovoltaic system are not affected.