The invention relates to a power supply control device for a power 
amplifier tube and a power-on and power-off control method thereof. The device comprises an MCU (Microprogrammed 
Control Unit) module, a temperature sampling module, a 
voltage DAC (
Digital to Analog Converter) module, a power supply module and a drain 
electrode power supply control module; the MCU module is user for controlling the drain 
electrode power supply of the power 
amplifier tube and the 
negative voltage power supply of a grid in a unified mode, and the 
grid voltage can be conveniently, quickly and dynamically adjusted through the control of the 
negative voltage power supply of the grid, so that self-adapted dynamic adjustment under different working temperatures is realized, and 
correctness and reliability for power-on and power-off sequence of the power 
amplifier tube are ensured through the combination of the control of the grid power supply, thus the power amplifier tube can be better protected from being burnt by incorrect power-on and power-off timing sequence, the power-on and power-off control timing sequence of the power amplifier tube is met, the power amplifier tube is always at a good working condition, and the reliability of power amplification 
system is promoted. According to the power supply control device for the power amplifier tube, the 
correctness and reliability for power-on and power-off sequence of the power amplifier tube are ensured, and the reliability of the whole power amplification 
system is directly promoted.