Abstract: To investigate the mechanics and hydrodynamics mechanism of the metal and double-antibody net for water and sand inrush under the caving zone, model test and penetration test has been combined in this paper. The steel model with 50 × 50 × 20cm has been designed to support the metal and double-antibody net to be conducted the pressurized test. The comparison penetration tests of four particle size sand have been conducted in this paper. It shows that the metal and double-antibody net can withstand great load without damage; the double-antibody net plays a great role to prevent the sand from subsurface erosion and block the sand collapsing inrush into the underground space. The permeability of four particles sands decreases after laying the double-antibody net, especially the small particle is more obvious, the decrease of permeability and the ratio of decrease when laying the double-antibody net at the bottom is bigger than it when laying the double-antibody net in the middle. The decrease of permeability when laying in the middle and at the bottom is the biggest in these tests, he decrease of permeability is bigger as the particle is smaller. The stable roof will be enhanced when laying the metal and double-antibody net in coal mining.