The utility model relates to an active lime production device of a rotary kiln. The active lime production device comprises a pulverized coal preparation portion, lime stone preheated kilning portion, a finished product screening storage and transport portion and a dust removal portion. A quantitative coal feeder of the pulverized coal preparation portion is communicated with a high-efficiency high-fineness ball mill via a hot blast heater, the high-efficiency high-fineness ball mill is communicated with a dynamic coal grinding powder concentrator which is further communicated with a powder collector, and a pulverized powder bin is arranged below the powder collector. A powder screen and a lime stone powder bin of the lime stone preheated kilning portion are communicated with the rotary kiln. The finished product screening storage and transport portion includes a finished powder bin and a finished block bin. The active lime production device can adopt low-volatile coals such as high-quality bituminous coal, anthracite coal, poor-quality bituminous coal or coal mixture of the high-quality bituminous coal, the anthracite coal, the poor-quality bituminous coal as kilning fuels.