The invention relates to a transformer substation direct current power supply system for monitoring a storage battery and a charging module and a monitoring method. The system comprises a monitor; thestorage battery and the charging module are controlled to output in turn through the monitor; and whether the storage battery and the charging module are abnormal nor not is detected. According to the transformer substation direct current power supply system for monitoring the storage battery and the charging module and the monitoring method, the damaged charging module or the charging module with poor input and output circuit contact can be discovered, the existing defect is discovered in time and disposed; and the monitoring reliability of the direct current power supply monitor for the storage battery is improved.