A coke control reactor, and a device and method for preparing low-carbon olefins from an oxygen-containing compound are provided. The coke control reactor includes a coke control reactor shell, a reaction zone I, and a coke controlled catalyst settling zone; a cross-sectional area at any position of the reaction zone I is less than that of the coke controlled catalyst settling zone; n baffles are arranged in a vertical direction in the reaction zone I; the n baffles divide the reaction zone I into m reaction zone I subzones; and a catalyst circulation hole is formed in each of the baffles, such that a catalyst flows in the reaction zone I in a preset manner. A catalyst charge in the present coke control reactor can be automatically adjusted, and an average residence time of a catalyst in the coke control reactor can be controlled by changing process operating conditions.