The invention provides a process for sealing a ground layer by casing pipes. The process for sealing the ground layer by the casing pipes at least includes the following steps that (1) a first collapse layer is drilled by a drill bit and sealed by the casing pipe; (2) after the first collapse ground layer is drilled, 20-30 meters are further drilled, a tank of concentrated liquids in 40 cubic centimeters is prepared to clean well holes, the recycling is performed for over two weeks, and 99.7% by weight of clean water and 0.3% by weight of collapse resistant agents ZNP-1 are blended to form the concentrated liquids; (3) the casing pipes are placed, the placing speed is controlled in the casing pipe placing process, and primary slurry is timely filled each time 30 casing pipes are placed; (4) the torque of the casing pipes is 10KN.M in the buckling process; (5) as for well cementation displacement volume, the displacement volume is accurately calculated according to the depth of the casing pipes before well cementation, and the thickness of cement plugs is calculated in advance according to displacement volume data after rubber plugs are pressed for checking to finish primary spudding well; (6) after the well cementation, wait on cement is performed for 48 hours, the cement plugs are drilled, and matched drilling liquids are used according to different ground layers to perform secondary spudding well until a target layer is drilled. By means of the process for sealing the ground layer by the casing pipes, technical problems of well leakage and collapse are effectively solved, the drilling speed is greatly increased, and the drilling period is shortened.