The pure-silica hollow-core fiber (HCF) has excellent thermostabilities that can benefit a lot of high-temperature sensing applications. The air-core microstructure of the HCF provides an inherent gas container, which can be a good candidate for gas or gas pressure sensing. This paper reviews our continuous efforts to design, fabricate, and characterize the high-temperature and high-pressure sensors with HCFs, aiming at improving the sensing performances such as dynamic range, sensitivity, and linearity. With the breakthrough advances in novel anti-resonant HCFs, sensing of high temperature and high pressure with HCFs will continuously progress and find increasing applications.