Abstract: At prepsent，Tuha Oilfield is in the development of mid-high water cut stage. When the effect of chemical tracer application was not obvious, the tritium isotope tracer technique was recommended. Tritium isotope was added to the injection fluids and injected to reservoirs during the process of oilfield development. Afterwards, by analyzing oil samples to monitor the concentration of tritium-isotope tracer from offset producers, the isotope production curve will be obtained. The curve is very helpful to evaluate both the heterogeneity and the connectivity of reservoirs as well as give direct evidence for profile control of both producers and injectors. The field application showed that this method was effective, and will be a direction to the adjustment of intermediary and later stage-oilfields.