At present the geoscience progress demands the conceptual change from past view point regarding the Earth as solid to one regarding the Earth as fluid or plastic. The socalled fluids (in a broad sense)includes the magmas,aqueous solution and gases. The solid can not flow unless it has been permeated by the fluids which are able to accelerate the strain rate. The three spieces mentioned above are not equivalent to each other in geodynamics. Research has demonstrated that the magmas and aqueous solution are the derivatives of the gases. The thermal conductivity of silicate solid is less efficient and very slow. So the gas geodynamics is the most vital factor in the fluid geodynamics. Here the gases infer to the mantle gases, which are basically different from the crust ones.