Methods for preparing micro-particles using a double emulsion technique combining a membrane and a micro-sieve are provided. Particularly the present invention relates to method for preparing micro-particles comprising: preparing a first phase comprising an active agent； preparing a second phase comprising a carrier and a solvent； passing the first phase and the second phase through a membrane to form a primary emulsion； passing the primary emulsion through a micro-sieve in a continuous phase to form a secondary emulsion； and removing the solvent to form the micro-particles.
