The invention provides a simple and convenient preparation method of avibactam, which uses piperidine-5-ketone-2S-formate II as a raw material, undergoes a condensation reaction with O-protecting group hydroxylamine hydrochloride, and then undergoes reduction, chiral Resolution and hydrolysis under alkaline conditions to obtain 5R-substituent oxyaminopiperidine-2S-carboxylic acid V; and then "one-pot" cyclic urealation, acyl chloride and amidation with phosgene, solid phosgene or diphosgene Reaction, through deprotection, sulfuric acid esterification, tetrabutylammonium into salt to obtain {[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazacyclo[3.2.1] Octane-6-yl]oxyl}sulfonyl tetra-n-butylammonium salt VII, and finally avibactam I was obtained by ion exchange. The invention has simple preparation route, easy operation, low raw material price, low cost, low discharge of "three wastes", high atom utilization rate, economical and environmental protection, and high yield of each step, which is beneficial to the industrialized production of avibactam.