In response to the serious barium / strontium – scale in oilfields, we simulated oilfield conditions and investigated the scale inhibition performance of several common scale inhibitors to barium and strontium, by following the protocol from Evaluation Methods of Anti-Scale Agent for Oilfield Use, Petroleum Gas Standards of People’s Republic of China SY/T 5673. The most effective scale inhibitor CD-1 was screened out. With CD-1 as barium / strontium scale inhibitor in the static anti-scale analytical experiments, the dependence of scale inhibition performance on scale inhibitor concentration, saltiness, temperature, time and the system pH was investigated. The application conditions of barium / strontium scale inhibitor in real petroleum and gas field was obtained. Under the optimized application conditions, the mixture scale inhibitor had better scale inhibition efficiency than CD-1 alone.