The rheological characteristic parameters of five lithium complex lubricating greases were determined. The comparison of rheological characteristic parameters and microstructure of the five greases was made. The results showed that the knowledge of the rheological properties of lubricating greases may contribute to reflect the change of the thickener structure. The flow transition index characterized the breaking behavior of inner structure of grease, the greater this index, the better that soap fiber structure of grease; The damping factor was shifted from a medium range towards a lower value which resulted in brittle character of sample. At a constant shear rate, the soap fiber structure of complex lithium grease is dense and uniform, apparent viscosity decline rate is small. In this sense, it is relevant to understand how the development of the soap fiber structures in the grease contributes to several functional and rheological properties of lubricating greases.