The study of the paleoenvironment and paleoclimate during the depositional period of the Middle Jurassic Shaximiao Formation in the central Sichuan basin has important theoretical and practical implications for revealing sedimentary patterns, reconstructing paleogeography, and understanding the oil and gas formation and evolution within the basin during that period. This paper analyzed 47 mudstone samples obtained from well Yongqian 1, utilizing variations in major and trace elements to reconstruct the paleoenvironment and paleoclimate evolution. The results show that the Sr/Ba ratio, Rb/K2O ratio, Ca/Mg ratio, and Ca/(Ca+Fe) ratio indicate that the Middle Jurassic Shaximiao Formation was mainly deposited in a freshwater environment. However, a temporary increase in salinity occurred in the middle and late depositional periods of the first member of the Shaximiao Formation. The V/(V+Ni) ratio, U/Th ratio, V/Cr ratio, and Ni/Co ratio suggest that the Shaximiao Formation depositional period was generally characterized by shallow wateroxidizing conditions with intermittent exposure and localized weakly oxidizing or reducing environments. The C value, CIA value, and Rb/Sr ratio indicate that the paleoclimate during the Shaximiao Formation depositional period was predominantly warm and humid but experienced intermittent fluctuations, ranging from warm and humid to semiarid to semihumid conditions. The multivariate geochemical parameters provide new evidence for the paleoclimate evolution of the Middle Jurassic Shaximiao Formation during its depositional period in the central Sichuan basin, which is beneficial for the regional paleoclimate comparison.