The invention relates to a method for preparing 
dexmedetomidine hydroch. The method particularly includes the following steps that 1, dispinner 
medetomidine is dissolved in methyl 
alcohol and mixed with a right-handed resolving agent according to the 
molar ratio of 1:0.4-0.6, stirring is conducted for 2-3 hours at the 
heating temperature of 60-80 DEG C, 
diethyl ether is added, cooling, still standing, 
crystallization and filtering are conducted, a mother solution and a left-handed resolving agent are mixed according to the 
molar ratio of 1:0.4-0.6, stirring and 
crystallization are conducted for 24 hours, and 
dexmedetomidine is obtained after filtering is completed; 2, obtained 
dexmedetomidine is placed in HCl / 
diethyl ether, and the end product dexmedetomidine hydroch is formed. Compared with the prior art, dexmedetomidine hydroch is prepared at low cost; the synthetic 
route is short, dexmedetomidine hydroch with high purity can be prepared, isomers are not detected, quality meets the newest standard of the pharmacopeia, and industrial production is facilitated. Adopted raw materials are low in cost, 
reaction conditions are moderate, and the method can be applied to actual production.