It is planning to drill an extremely deep hole with depth of 13000m in China that has great significance. In deep drilling， particularly in superdeep drilling it is a difficult problem to transfer the bottom hole drilling parameters to the surface in time and correctly and to adjust and control them so that the normal drilling and good technical and economic results can be guaranteed. Russian experts propose a combination link channel and that has definite reference value probably. It is very important to have an automatic control system to solve the problem of how to adjust and control the bottom hole drilling fluid pressure in order to guarantee the normal drilling and prevent accident and how to resolve the response lateness of signal in the link channel. Russian scientists have done a lot of work in these fields and got a definite success and that deserves our attention.