The invention discloses a composite acid 
pickling corrosion inhibitor of barbadosnut cake 
meal extract and a preparation method of the composite acid 
pickling corrosion inhibitor, and belongs to the technical field of 
corrosion inhibitors. The process of extracting an 
acid corrosion inhibitor from barbadosnut cake 
meal is optimized, toxalbumin and 
phorbol ester are removed, the problem that the 
acid corrosion inhibitor extracted from the barbadosnut cake 
meal is toxic is solved, shaddock peel extract and the barbadosnut cake meal extract suffer from synergistic interaction, the corrosion inhibition efficiency is high, high adaptability is achieved, the effect of corrosion of acid on steel and aluminum is obviously inhibited, and more importantly, a good corrosion inhibition effect is achieved for 
zinc and 
zinc and aluminum 
alloy. The 
corrosion inhibitor is safe, free of harm, biodegradable and convenient to use, can be applied to washing 
petrochemical equipment, boilers and even 
tap water pipelines, and has good development prospects.