Abstract: The radioactive isotope tracer position can be detect sensitively in logging. In order to accurately measure contaminated isotope position and amount, improve the reliability of the isotope tracer injection profile evaluating result, the feasibility of radioactive isotope tracer detection technique in logging is research. The contents concern in the development of radioactive isotope tracer energy spectrum logging device, the calibration experiment in model well, the analysis of experimental data, the data (interpret)-ing, and so on. The result shows that radioactive isotope tracer petroleum logging technique possesses favorable application prospect both in theory and in production.