A facile and reproducible method based on microreaction technology has been developed for the continuous preparation of layered double hydroxides (LDHs) with narrow particle size distribution. Mg–Al–CO3, Mg–Al–NO3, Mg–Al–Cl, and other different kinds of LDHs containing binary, ternary, and quadruple metal cations were successfully prepared. Due to the enhanced mixing, a high slurry throughput of 300 mL/min in a single reaction channel was obtained.