Antisolvent crystallization is an important purification technology for the pharmaceutical and fine chemical industries. Herein, we investigated the mass-transfer mechanism of membrane-assisted antisolvent crystallization (MAAC) and developed a multistage operation to reinforce the manufacturing features of antisolvent crystallization. Computational fluid dynamics simulation results via a developed mathematics model and the experimental images via in situ detection technology jointly illustrated the advantages of MAAC for accurate mass-transfer control. Further, a three-stage MAAC process was investigated to reveal the process control performance. The diverse functional regions of multistage MAAC under different antisolvent addition strategies were then highlighted by manufacturing the crystal products with a narrow size distribution, a uniform aspect ratio, and the desired morphology. Multistage MAAC that intensifies the product capacity under a stable control is a promising direction for new-generation antisolvent crystallization.