Abstract: To address the issues of DNA degradation and preservative contamination caused by rainwater infiltration in traditional pitfall trapping used for epigeic arthropod sampling, this study designed and field-tested a novel water-exclusion pitfall trap (WEPT)． This study aimed to enhance the quality of molecular data obtained from field samples in complex environments and to meet the demands of long-term biodiversity monitoring． Constructed using 3D printing technology, the WEPT integrates a water-guiding base with a funnel structure． Comparative field experiments were conducted during the rainy season in the Northeast China Tiger and Leopard National Park, involving the WEPT, a standard pitfall trap (PT), and a standard pitfall trap with ethanol (PTE)． The evaluation systematically assessed DNA preservation effectiveness (measured by PCR success rate) and arthropod capture efficiency (including abundance, species composition, and diversity indices)． The WEPT significantly improved the PCR success rate of samples to 86.21%, compared to 55.88% for the PT． Arthropods captured by the WEPT represented 11 orders and 38 families, with both richness and diversity indices significantly higher than those in the PT group． No significant difference was found in total abundance and community diversity between the WEPT and PTE groups, indicating that the WEPT maintained superior sample quality while achieving capture efficiency comparable to traditional methods． These findings confirm that the WEPT effectively overcomes the prevalent issue of DNA degradation due to rainwater infiltration． By combining reliable sample preservation with efficient collection, the WEPT provides a robust tool for arthropod diversity research and molecular monitoring in challenging field conditions, thereby advancing the standardization and application of biodiversity monitoring technologies．