A shutdown control system and a shutdown control method are provided. A main circuit is a series circuit formed by connecting multiple shutdown circuits in series or a series-parallel circuit formed by connecting multiple such series circuits in parallel. Each shutdown circuit is connected to at least one direct current power supply. A control circuit includes a SCU and multiple PCUs corresponding to the multiple shutdown circuits. The SCU and the PCUs are configured to transmit respective mode control instructions when respective condition is satisfied. Each PCU is configured to obtain multiple criteria based on the mode control instructions from the SCU and other PCUs, determine a target operation mode of the shutdown circuit corresponding to the PCU based on the multiple criteria, and control the shutdown circuit corresponding to the PCU to operate in the target operation mode.