This disclosure relates to medical diagnostic high-frequency X-ray machines and power supply devices thereof. One power supply device can convert an alternating current into a direct current, which is further raised by a boost circuit and stored by a capacitor module, so that the power supply device can provide high voltage and sufficient power to an inverter. Another power supply device can use a lithium iron phosphate battery to power the X-ray machine. Accordingly, the X-ray machine can be lighter, smaller, resistant to high temperature, fast in electrical charging and discharging, and safer, and the usage life of the X-ray machine can be prolonged due to the long cycle life of the lithium iron phosphate battery.
