Sharks are one of the most threatened groups of marine animals, as high exploitation rates combined with low resilience to fishing pressure have led to population declines worldwidely. Designing conservation strategies for sharks depends on basic knowledge of the geographic distribution and diversity of known species. So far, this information has been fragmented and incomplete. In this study, observer data from 1 874 sets of Chinese tuna longline fisheries in the Eastern and Central Pacific were used to estimate the biodiversity of sharks by applying alpha diversity measures, such as species richness, Chao2 index, Shannon index, species evenness, species density and rank-abundance curves, and the relationships of species richness and Shannon index with spatiotemporal and environmental factors, such as year, season, latitude, longitude, sea surface temperature, chlorophyll-a, and sea level anomaly were analyzed using the generalized additive models. Results showed that a total number of 20 sharks were observed, mainly consisting of <italic>Prionace glauca</italic> and <italic>Carcharhinus falciformis</italic> in the Eastern and Central Pacific. We found that there was a similar species composition in the Eastern and Central Tropical Pacific (Chao2=23.98) and Southeastern Pacific (Chao2=22.50), but the species evenness in the Tropical Pacific was higher than that in the Southeastern Pacific. The shark community in the Eastern and Central Tropical Pacific was dominated by <italic>Prionace glauca</italic> (28.97%) and <italic>Carcharhinus falciformis</italic> (23.85%), while in the Southeastern Pacific it was overwhelmingly dominated by <italic>Prionace glauca</italic> (76.64%). In the Eastern and Central Pacific, the biodiversity of sharks, such as species richness (<italic>S</italic>), Shannon Index (<italic>H</italic>’), and species density in the tropical area was higher than that in the temperate area. The species richness and diversity of sharks showed large spatiotemporal differences and were significantly influenced by habitat environmental characteristics. In terms of inter-annual variation, shark community diversity showed an increasing trend from 2012 to 2017 and a slight decrease from 2017 to 2019. The season with the highest diversity was the third season and the lowest diversity was found in the first season. Sharks preferred to inhabit the areas characterized by warm waters (sea surface temperature≈25℃), intermediate productivity concentrations (chlorophyll-a>0.10 mg·m<sup>-3</sup>) and abnormally low sea level (sea level anomaly < 0 m). The alpha diversity performed well in identifying hotspots of biodiversity. The study helps to understand the shark biodiversity in pelagic ecosystems and identify, for conservation purposes, the critical habitats of the shark’s community in tuna longline fisheries in the Eastern and Central Pacific Ocean, and contributes to the future implementation of the protected marine areas, fishing moratorium or restricted fishing zone to manage the pelagic ecosystem in a holistic and more integrated way.