Abstract: There are two problems in foam drilling. The first is that the foam obviously corrodes the steel drilling tools. Because of a large quantity of water and air in the foam and oxygen in the air, the steel drilling tools are corroded mainly by water and oxygen. Foam agent also plays an important part in the course of oxygenating and rust-eating. The anticorrosive measures are thus put forward. The second is the forming of foam. Material and mechanism are two essential elements for the forming of stable foam. Without air, pure liquid can't foam and without foam agent, stable foam can't form. While without mechanism, the air can't enter the liquid film, so the stable liquid also can't foam, even if it contacts gas. A special kind of foam generator is used for the solution of the problem.