The high-pressure back-flush valve features an upward movement closure structure, enabling simultaneous shutdown and instant back-flush to cut off the material, reducing residual flow on the remaining needle, and preventing phenomena such as leakage and stringing of the medium. Suitable for high-viscosity liquid substances, with an attached back-flush function; includes a piston stroke adjustment structure and a back-flush structure to prevent liquid leakage; assisted by an auxiliary air inlet for closure.