The invention discloses a hydroxylamine hydrochloride synthesis method which comprises the following steps: putting pinacolone oxime and a concentrated hydrochloric acid solution into a kettle in a mole ratio of 1.2-1.5 to 1, intensely stirring, heating to 70-80 DEG C, and carrying out hydrolysis; cooling, leaving to stand and layer, collecting an upper layer, namely pinacolone, and a lower layer,namely a hydroxylamine hydrochloride solution, carrying out vacuum distillation on a water layer, separating a white crystal in the kettle, adding ethanol, cooling, crystallizing, and filtering, so as to obtain hydroxylamine hydrochloride of high purity and high yield. By adopting the hydroxylamine hydrochloride synthesis method, side reactions in a hydrolysis process can be avoided, the purity of hydroxylamine hydrochloride can be improved, the yield of the hydroxylamine hydrochloride can be increased, in addition, the method has the characteristics of being simple in step, easy in raw material obtaining, small in wastewater amount, good in environmental-friendliness, and the like.