For antibiotics, the purification and separation in the synthesis process, as well as enrichment and recycling in the utilization process, has a profound impact on human health and environmental issues, which pose an unignorable challenge for selective molecular sieving of separation technology. Herein, we offered a convenient high-accuracy separation membrane construction by using three dimensional rigid triptycenes as building-blocks to fabricate porous triptycene networks polyarylate nanofilms (PTN-NFs) by interfacial polymerization. With permanent porous structure and excellent stability, the PTN-NF membrane exhibited remarkable separation precision around 90 g mol−1 scale for several mixture separation and significant selectivity as high as 39.3 for piperacillin/6-aminopenicillanic acid (6-APA) separation.