Intergrain fluids within the nonhydrostatically stressed solids under low temperature play a very important role in deformation and syntectonic geochemical processes for the intergrain fluid-mineral reactions and the mass-transfer by intergrain fluids. The state and nature of inter-grain fluids, the reactions of inter-grain fluids with minerals, and the mass transfer by intergrain fluids are all closely related to stress of solid grains. Through theoretical analysis, the water film is thought of being the main state of intergrain fluids in the nonhydrostatically stressed solids. Whether hydration force, double-layer repulsive force or osmotic pressure due to double-layer is the main mechanism for transmitting stress mainly depends on thickness and composition of the fluid film. The contribution of stress to solid-fluid interface reaction
and mass transfer by fluids is that stress can enhance the free energy of solid matter on the interfaces. The thermodynamic and kinetic equations for the stress induced processes are deduced in this paper.