Abstract: Based on the theory of geological control and rock hydromechanics, this pape r insists that the geotexture governs fluid flow in rock masses most directly. T he geotexture is graded properly with consideration on the characteristics of fl uid flow in rocks. Four important effects of geotexture on fluid flow are propos ed, i.e., the graded preference effect, the channeling intersection effect, the unsaturation effect and the coupling effect. The basic meaning, relationships an d engineering significance of these four effects are preliminarily discussed.