Abstract: The log of PNN records heat neutron rates during seized reaction. The macro seized section could be attained from that reaction and applied for calculating saturation of remained oil.The article com pared PNN logging technology with neutron-lifetime logging technology, and discussed interpretation method and adaptability of PNN logging.It is believed that macro seized section is a parameter of neutron attribute. There are relativity among macro seized section, nature gamm a curve of open well and character of reservoir. Interpretation result of PNN and open well is coherent. The author thinks interpretation result can't be qualitative when average mineralization of formation water is about 1000mg/L, because macro seized section of rinsing and oil formation is adjacent. Interpretation result can been qualitative when average mineralization of formation water is about 6000mg/L. We can interpret correctly by consulting the history of oil well and water injection of adjacent well.