In order to solve the problem that waste water transportation costs of Dalaoba gas gathering station is high and quality of water injected into Well DLK8 cannot meet relative standards, conducted is optimization on water injection process of Well DLK8 and applied is a new microbial waste water treatment process so as to make the quality of treated waste water meet requirements of Well DLK8 water injection. Through water injection process optimization, waste water transportation costs of Dalaoba gas gathering station has been reduced obviously, quality of treated waste water has been improved greatly and pollution of waste water on the environment has been relieved efficiently. Due to application of microbial waste water treatment technology, efficient water injection has been realized in Well DLK8, Dalaoba No. 1 tectonic strata pressure is kept, retrograde condensation is lowered and the strata gas recovery is improved.