In deep drilling， the high temperature and high pressure environment underground places higher requirements on the performance of drilling fluids. Rheology is an important property of drilling fluid， and ensuring the stability of drilling fluid rheological properties under high temperature and high pressure conditions is a necessary prerequisite for safe drilling in deep wells. High temperature and high pressure drilling fluid rheometers are important to measure the high temperature and high pressure rheological properties of drilling fluid. This article briefly introduces three high temperature and high pressure drilling fluid rheometers that are currently needed in deep drilling， including their functional characteristics， main technical parameters， and applications. The aim is to provide reference for drilling workers to correctly select relevant testing instruments， improve drilling safety and efficiency.