The separation stability under high-humidity is significant in practical applications for air filters. Herein, hydrophobic polyvinyl chloride (PVC) nanofiber filters with bead-on-string structure are designed to steadily remove particle matter under high relative humidity of 90%-95%. The developed hydrophobic filters possess comparable separation performance with the hydrophilic one, but greatly enhanced stability. After the introduction of beadon-string structure, the filtration performance can be furtherly improved due to the formed large cavities and hydrophobicity. Such hydrophobic PVC filters can be promising candidates for air purification in practical applications especially in wet seasons. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.