Hollow fiber-based gas separation membranes have attracted considerable attention due to their commercially favorale configuration. However, high affinity between selective polymer layers and porous substrates leads to spontaneous polymer infiltration into the porous substrate, resulting in undesired performance degradation. To address this, we here develop an automated hollow fiber coating process coupled with in-situ air-assisted drying. This commercially friendly system effectively minimizes the penetration of polymer coating solution into porous support, confirming various characterizations such as depth-profiling XPS. As a result, gas separation performance is dramatically improved through optimized selective thickness and suppressed polymer infiltration. Furthermore, a practical relevant module demonstrates enhanced H2 separation performance under mixed gas conditions.