Rheology modifier, which mainly to increase the shear force and viscosity is a key additive to improve rheology of drilling fluid so that the drilling fluid has a higher dynamic plastic ratio and better shear dilution. With the development of ERD, high-angle directional well, deep water well, ultra-deep water etc., it is difficult for drilling fluids to have effective rheology in complex formations which often occurs problems such as insufficient viscosity and shear, excessive degradation and even loss the capacity of suspension and carrying. Especially, the problem of insufficient wellbore cleaning often appeared in the large displacement wells and complex wells. This article mainly introduces the research progress and application of existing rheology modifiers for drilling fluids. According to the type of drilling fluid, it is divided into: rheology modifier for typical drilling fluid, rheology modifier for flat-rheological drilling fluid and rheology modifier for other drilling fluid. Firstly, the author compare and evaluate the ability of increase viscosity and cutting, temperature resistance, environmental protection and price advantage of different rheology modifier for drilling fluids and then proposed suggestions for the future development of rheology modifier in order to provide information and references.