Preparation of defect-free and optimized thin film nanocomposite (TFN) membranes is an effective way to enhance the process of organic solvent nanofiltration. However, it still remains a great challenge due to poor filler particle dispersibility in organic phase and compatible issue between fillers and polymers. Aiming at these difficulties, UiO-66-NH2 nanoparticles were surface modified with long alkyl chains and used in the preparation of TFN membranes. As a result, defect-free TFN membranes with ultrathin MOF@ polyamide layer were successfully prepared benefited from the improved particle dispersibility in n-hexane. Significant enhancement was found in methanol permeance after nanoparticle incorporation, without comprising the tetracycline rejection evidently. Especially, the novel TFN membrane prepared with organic phase solution containing 0.15% (w/v) modified UiO-66-NH2 nanoparticles showed a superior methanol permeance of 20 L center dot m(-2)center dot h(-1)center dot bar(-1) and a tetracycline rejection of about 99%, which is appealing to the application in pharmaceutical industry for example. (C) 2016 American Institute of Chemical Engineers AIChE J, 63: 1303-1312, 2017