In order to improve the wetting reversal and flushing effect of the flushing fluid for oil-based drilling fluid，the emulsion was formed by the cloud point effect of isomeric alcohol polyoxyethylene ether and octylphenol polyoxyethylene ether. At the same time，it was compounded with sodium diisooctyl sulfosuccinate（fast T）and span 60. By investigating the flushing efficiency and phase transition temperature of the flushing fluid，the formula of the flushing fluid was determined as follows，15% isomeric decanol polyoxyethylene ether（E1008）+ 6% octylphenol polyoxyethylene ether（OP-10）+ 3% fast T + 3% spandex 60. The temperature resistance，flushing efficiency，compatibility of the flushing fluid was investigated，the bond strength of cement after flushing with the flushing fluid was tested. The results showed that the flushing fluid had a temperature resistance of 170 ℃，and the flushing efficiency of 20% flushing fluid and spacer fluid was more than 95% within 7 min at 50—170 ℃. After flushing，the wellbore surface realized wetting reversal. The flushing fluid had good compatibility with drilling fluid and cement slurry. The flushing fluid had been applied in 10 wells and achieved good cementing quality.