A heat dissipating structure of a 1U power supply is installed in an industrial computer host system of a universal standard specification 1U for supplying electric power, and at least one wall of the power supply differentiates a retaining plane and a heat dissipating plane having a heat dissipating hole with a height difference, and a horizontal plane of the heat dissipating plane is lower than the retaining plane and forms an airflow passage with the computer host system for guiding a heat dissipated airflow through the airflow passage to improve the poor heat dissipation at both distal ends of the traditional 1U power supply due to the same height of the power supply and the computer host system or the proximity of both sides of the power supply with an installed electronic device such as a hard disk.