Abstract: As a typical front type, penetrating fronts (PF) significantly affects cross-shelf substance transport and play an important role in regulating the regional biogeochemical-ecological processes. Based on data for temperature, salinity, nutrients and Chlorophyll a (Chl a) collected during spring 2017 in the Changjiang Estuary and the inner shelf of the East China Sea, this study explored the influences and mechanisms of penetrating front on the distributions of nutrients and Chl a. The results show that the low-salinity water off the Changjiang Estuary presents a multidirectional transport pattern in the upper layers, and two PFs expanding southeastward forms in the southeast of Zhoushan Islands and near 124°E to the east of Hangzhou Bay. The low-salinity water can be transported offshore by the PF over long distances from the nearshore, generating strong haloclines within their influenced areas. Tongue-shaped high-nutrient zones extending seaward from the coast were observed in the Changjiang Estuary-East China Sea inner shelf, generally corresponding to the position of the PFs, demonstrating their role in transporting nutrients. Driven by the nutrient supply from the PF, a high-Chl a zone in a double-tongue shape formed in the east of Hangzhou Bay and southeast of Zhoushan Islands, and its position matches well with the two PFs. Meanwhile, favorable light conditions and high water column stability in the PF-dominated region also promoted phytoplankton blooms and biomass accumulation, thus leading to the formation of high-Chl a zone. This study provides an important scientific basis for further understanding of the impacts of PF on the biogenic element cycling, primary production and ecosystem on the East China Sea shelf.