The development of eco-friendly methods for producing uniform-sized gold nanoparticles (AuNPs) has gained attention due to the hazardous effects of chemical synthesis processes. Here, we present a green synthesis method using diastase from Aspergillus oryzae, which serves as both a reducing and stabilizing agent without the need for additional chemical reagents or surfactants. These nanoparticles have promising applications in biocatalysis and environmental remediation due to their shape and size-dependent properties. However, achieving controlled size and shape on a large scale remains challenging as it depends on the concentration of reagents. To address this, we developed a continuous synthesis approach using a microfluidic channel, which offers several advantages over conventional batch synthesis techniques. The continuous and controlled flow of reagents within the microfluidic channel leads to the sustained formation of AuNPs. It also allows for determining optimal reagent concentrations to produce AuNPs of the required shape and size. This setup enables rapid, cost-effective, and scalable high-flux production of gold nanoparticles with high reproducibility without compromising the properties of AuNPs. This approach aims to establish robust and reproducible continuous flow synthesis procedures for gold nanoparticles using diastase as a reducing agent.