The invention discloses a method for preparing a perovskite quantum dot nanorod from methylamine lead bromide perovskite quantum dots. The method comprises the steps of (1) cleaning a glass slide, firstly pouring a piranha solution (concentrated sulfuric acid and 30% hydrogen peroxide at the ratio of 7:3), boiling for 30min, sequentially pouring an ethanol solution and a deionized water solution, carrying out ultrasonic cleaning for 15-30min separately, taking out the glass slide and blowing by using nitrogen; (2) dissolving a dimethylformamide DMF solution of the methylamine lead bromide perovskite quantum dots into methylbenzene to prepare 1*10<-4> to 1*10<-3>mol/L of methylamine lead bromide perovskite quantum dot methylbenzene solution; (3) dripping the methylamine lead bromide perovskite quantum dot methylbenzene solution on the glass slide in a culture dish; and (4) closing a lid of the culture dish, drying the methylamine lead bromide perovskite quantum dot methylbenzene solution at a room temperature to obtain the perovskite quantum dot nanorod. A light-emitting layer for building a novel LED device, which is good in machinability and relatively low in cost, and can be produced on a large scale is provided for the field of solid-state lighting.