Novel in-flow digital lithography for massive and high throughput synthesis of microparticles is developed. Microfluidic environment offers great platform to transport multiple functional materials in the flow stream. By innovative application of the 3D digital micro/nanofabrication techniques using a digital dynamic display, geometrically and chemically anisotropic microparticles can be rapidly fabricated while the fluid is flowing. Multiple functional units with different optical, chemical, or mechanical properties can be possibly encoded into the particles, making it possible to program subsequent self-assembly process of the fabricated particles. Therefore, these functional units can be potentially used as building blocks for large scale metamaterials.