Rheological phenomenon of the concrete faced rockfill dam can be critical according to prototype monitoring. In view of the three-dimensional shear rheological rate formulas of rockfill material are different in different documents. Three-dimensional rheological rate of rockfill material is studied with the rheological model of 3 parameters as an example. Volume rheology and shear rheology are assumed different. First of all

the three-dimensional volume rheological rate formula is deduced; and then

based on Prandtl-Reuss flow rule

it can be derived by Mises yield function as a plastic potential function. The computational formula of three-dimensional shear rheological rate of rockfill material is derived taking associated flow rule and assuming that the plastic potential function is Mises yield function. The theory of the computational formula of three-dimensional rheological rate is rigorous

since the computational formula of three-dimensional rheological rate can degrade into the computational formula of uniaxial state. Thus it is pointed out that the theory of the computational formula of three-dimensional rheological rate in related papers is not rigorous.