The deformation of surrounding rock of slate tunnel after excavation is fast, large and lasting for a long time, which affects the safety of tunnel construction and the long-term stability of later operation. Taking a highway tunnel under construction in Southwest China as the research background, the field monitoring test of surrounding rock displacement and temperature for 0~120 days is carried out. The test results show that: (1)The tunnel has strong environmental sensitivity, the surrounding rock stress is released after tunnel excavation, and the surrounding rock is in tension state and creep accumulation;(2)The displacement of surrounding rock shows a power-law accumulation law. The accumulation rate is fast from 0 to 60 days, and gradually slows down after 60 days. At 120 days, the displacement time history curve tends to converge, with the maximum displacement of -9.93 mm and the minimum displacement of -0.05 mm;(3)The monitoring temperature of surrounding rock has an inverse proportional attenuation relationship with time, and the temperature gradually decreases with time. After 120 days, the final temperature will be basically consistent with the outdoor temperature. Based on the law of temperature change, the improved Harris temperature time relationship expression is established and embedded into the head creep model, so as to obtain a new improved head creep constitutive model considering temperature effect. The feasibility and rationality of the model are verified, and the creep deformation law of surrounding rock after 500 days is predicted by using the model. The research results provide a certain reference for the study of creep characteristics of tunnel surrounding rock and tunnel construction and operation.