Since bio-competitive exclusion（BCX）is low in cost，broad in processing range and simple in operation，it has becomean important technology for the management of sulfate-reducing bacteria（SRB）in the reservoir. However，the on-site injection process has remained a main bottleneck，limiting the use of BCX technology. Simulating the formation condition，the SRB inhibitor（nitrates）were injected into formation water daily or at one time during a laboratory research，which eventually facilitated the breeding of nitrate-reducing bacteria（NRB）. In this case，the amount and metabolism of SRB were under control. This research aimed to evaluate the influence of different nitrates injection on the concentration of SO42-，NO3-，NO2- and H2S and the quantities of SRB and NRB. The results showed that compared with the injection at one time，daily injection could not restrict the decrease of SO42- effectively while NO3- and NO2- remained a low level. Moreover，both methods did not produce H2S. In the early stage of management，injection at one time produced more NRB than the daily injection. In the late stage，SRB was restricted，and daily injection presented a more inhibitive effect. During the SRB management，excessive nitrate was injected in the early stage to stimulate the growth of NRB and inhibit SRB. Later，small dosage of drugs with continuous injection could be used to maintain the above inhibitive effect.