The invention provides a preparation method of 
brown rice ferment, and belongs to the technical field of production of foods. The method comprises the following steps of firstly cleaning 
brown rice, soaking the cleaned 
brown rice, performing culturing in a 32 DEG 
C constant-temperature culturing box until the brown rice sprouts, placing the sprouted brown rice in a baking box of 50-55 DEG C, performing 
drying, and after the 
water content of the sprouted brown rice is smaller than 15%, 
grinding the dried sprouted brown rice into 
powder so as to obtain the sprouted brown rice 
powder; and mixingthe sprouted brown rice 
powder with honey, white granulated 
sugar, table salt, a 
vanilla extract and water according to a certain formula proportion to obtain a culture solution, placing the culture solution at 121 DEG C, performing sterilization for 20min, after the culture solution is cooled to 40 DEG C or below, performing 
inoculation with 
lactic acid bacteria, placing the culture solution inoculated with the 
lactic acid bacteria in a 40-42 DEG 
C constant-temperature culturing box, and performing culturing for 6-10h so as to obtain the brown rice ferment. The brown rice ferment processed bythe preparation method disclosed by the invention can be directly drunk as a beverage, and has favorable mouth feel and taste, high 
nutrition components in rice are reserved, and the economic value of the rice is increased.