An all-day multifunctional telescope device capable of being both used for solar active region observation and night astronomical observation comprises an optical telescope system, a lightweight cellular main lens and temperature control system, a thermovision field diaphragm and temperature control system, a thermovision field diaphragm adjusting structure, an achromatic imaging system, a light filter, a rotating rack and a data processing and control system. According to the all-day multifunctional telescope device capable of being both used for solar active region observation and night astronomical observation, under the condition that cost and system complexity are not obviously increased, the effective observation time of the telescope device is changed to achieve daytime and night continuous observation from only daytime or night observation, the effective observation time is effectively prolonged, the observation efficiency is improved, important reference is provided for development of telescopes, in particular to development of large-diameter telescopes, and the innovativeness and practicability are achieved.