A power supply with a staggered configuration includes a housing having an accommodation space, a first power supply module, a second power supply module, and an electric fan which are disposed inside the accommodation space. The first power supply module includes a first frontend power conversion unit and a first backend power conversion unit which are disposed at separate airflow passages. When the power supply is in operation, the electric fan turns and drives the air to flow into the housing in such a way that one airflow passage is through the first frontend power conversion unit and another airflow passage is through the first backend power conversion unit. In this way, the heat dissipation efficiency is increased with two separated air flow passages respectively flowing through and cooling down the first frontend power conversion unit and the first backend power conversion unit.