The utility model discloses a heat dissipation structure of a transformer cabinet. The transformer comprises a transformer cabinet and a fan, a partition plate, a left air duct, a left flexible connector, a fan cover, an electric push rod, an air blocking plate, a right air duct and a right flexible connector are included. The partition plate divides the transformer cabinet into a left area and aright area from bottom to top, a transformer is placed in the left area, a control device is placed in the right area, when the electric push rod drives the air blocking plate to move downwards, the left flexible connector, the fan cover, the right flexible connector and the right air duct cavity are communicated, and the draught fan extracts hot air in the left area and the right area of the partition plate and discharges the hot air into air. When the electric push rod drives the air blocking plate to move downwards to block the ventilation opening, a channel between the left flexible connector and the fan cover is blocked, and the draught fan can only pump out hot air in the left side area of the partition plate and exhaust the hot air into air. The device is simple in structure, the control device and the transformer are placed separately, two heat dissipation modes are adopted, the heat dissipation effect and efficiency are effectively improved, the reliability of the control device and the transformer is improved, and the left flexible connection and the right flexible connection are convenient to install.