The Internet brings new opportunities and challenges to scientific development and science communication. Previous studies overwhelmingly focused on individual-level Internet factors but overlooked the potential explanatory strength of Internet context. This study addresses the existing gap by examining how the Internet influences Chinese people’s scientific optimism from a comprehensive perspective (Internet as a medium and Internet as a context). Multilevel models were built based on individual-provincial merged data. The results indicate that (1) the Internet context impairs scientific optimism while Internet exposure has no significant effect. (2) The relationship between individual Internet exposure and scientific optimism varies by province. As a quantitative indicator of Internet context, Internet penetration mitigates the weakening effect of individual Internet exposure on scientific optimism. This research provides empirical evidence on scientific attitude formation in the non-Western environment and expands the analytic approach of public attitudes toward science.