The fruit browning of Luffa cylindrica can lead to deterioration in their sensory and nutritional qualities. Polyphenol oxidase （PPO） is a key enzyme oxidizing phenolic compounds and responsible for the browning process. Therefore， evaluating the fruit browning of Luffa cylindrica germplasm resources and systematically analyzing the PPO gene family can provide material basis and genetic resources for browning research. In this study， the fruit browning evaluation was conducted on 158 Luffa cylindrica germplasm resources based on the a^* value in both 2022 and 2023， which identified 11 highly browning-resistant and 11 browning-sensitive germplasm resources. At the whole-genome level of Luffa cylindrica， seven PPO gene family members （LcPPO1-LcPPO7） were identified， which located on chromosome 6 and showed a cluster distribution. LcPPO1-LcPPO7 are all hydrophobic unstable proteins， located in the chloroplast and highly conserved. Correlation analysis was conducted between the gene expression of LcPPO1-LcPPO7 and the a^* value. Only LcPPO3 showed significantly positive correlation with a^* value， and it was highly expressed in the browning-sensitive germplasm resources. In addition， in the highly browning-resistant material Nuomi luffa（YN-20） and the browning-sensitive material Luo luffa（Z-37）， the gene expression of LcPPO3 and PPO activity showed significant differences， and compared with Nuomi luffa（YN-20）， the relative expression level of LcPPO3 and PPO activity in Luo luffa（Z-37） significantly increased with the extension of fresh-cut time， indicating that LcPPO3 is a key gene in the fruit browning of Luffa cylindrica. These results provide important material basis and theoretical basis for the study of Luffa cylindrica fruit browning and breeding of browning resistant varieties.