Acidifying multi-stage liquid supply system and process for oil-gas well large-scale acidifying and modifying

The invention provides an acidifying multi-stage liquid supply system for oil-gas well large-scale acidifying and modifying. The acidifying multi-stage liquid supply system comprises a plurality of acid tanks, a liquid supply pump, a buffer tank group, a liquid supply vehicle and a high-low-pressure distribution device which are sequentially connected through pipelines, wherein acid liquor accommodated in the acid tanks is in a low-pressure region at one side of a well mouth; the buffer tank group is composed of two or more buffer tanks which are mutually connected in parallel, and can preventacid liquid corrosion; the liquid supply pump communicates with the multiple acid tanks at the upstream, and the liquid supply vehicle and the high-low-pressure distribution device are used for sequentially providing the acid liquid to an oil-gas well well-mouth in acidifying and modifying. The acidifying multi-stage liquid supply system can improve medium-later-period liquid supply ability, keeps medium-later-period hig