Static correction and choosing datum are the key factors that directly affect the quality of the image when processing the seismic data acquired in Chinese northwest with complicated surface conditions. According to the experience of processing the land seismic data in recent years, the method of combination the surface parameters investigated in the field and refraction static correction is put forward. Firstly, atripping the layer with low-velocity to the top interface of the first layer with high velocity. Secondly, correcting the data to a final datum. Thirdly, separating the static correction values into two components, the long-wave length part and the short-wave length part. And then using the velocity derived from the CMP datum to stack the seismic data. Finally, migrating the stack data in the final datum, then the migration datum can be solved correctly in this way. Frankly the very way to solve the static correction accurately is tomigrate the data from the surface in depth domain.