The present invention mainly relates to a microwave drier, especially a microwave vacuum drier. A safe and energy-saving microwave vacuum continuous automatic drier includes a tank (A), a hoisting system (8), a vacuum system (9), a microwave heating system (1) on the tank (A), characterized by including a delivery device (6) inside the tank (A), a discharging device (5) below the delivery device (6), the materials in the tank (A) are non-metallic materials. On the basis of ensuring the strength and the toughness, the striking a light and discharging are avoided in the vacuum state when metal is heated in the microwave. The invention adopts the way of microwave radiation heating, utilizing the characters of microwave high efficiency, easy to control, antisepsis, sterilization, fast heating, even heating, fast dehydration, preserving to reduce the power waster and advance the efficiency.