Well A in Lüda oilfield is a thermal recovery well injecting with 350 ℃ high temperature and pressure steam for exploiting of heavy oil. The hydraulic control pipelines of the downhole monitoring equipments are corroded seriously. Scanning electron microscopy (SEM) and electron energy spectroscopy (EDS) were carried out for the corrosion test of hydraulic control pipelines. Meanwhile, the ion and corrosive gas compositions of produced water were analyzed. The results show that the main cause of the pipeline corrosion is from H₂S corrosion under high temperature, pressure and salinity conditions, accompanied by a small amount of chlorine and CO₂ corrosion. Under simulated site temperature, pressure and medium conditions, test pieces made of 316L, Inconel 625, P110 and 9Cr1Mo were selected and evaluated by dynamic simulation corrosion tests. Furthermore, weight loss method was used to evaluate the corrosion performance of the four materials. The results show that Inconel 625 material has the best corrosion resistance effect in heavy oil thermal recovery environment.