Abstract: The source water for water injection,source water after procession,water of an injection well,and oil crude of a production well were sampled and degassed.The ³He/⁴He,⁴He/²⁰Ne and ⁴⁰Ar/³⁶Ar of the gases from the waters and oils were analyzed.We found that they can be used for identifying the phenomena and degree of water flood of a production well.Our research shows that the ³He/⁴He,⁴He/²⁰Ne and ⁴⁰Ar/³⁶Ar of the source water for water injection,source water after procession and water of an injection well characterize an atmosphere source.The ⁴⁰Ar/³⁶Ar of crude oil in the Huangshatuo oil field is near that of the air in an error range,indicating that it was flooded by water and can be used as a tracer of water flood in an oil field,however it has no relation with ⁴He/²⁰Ne and can not be used for reflecting the degree of water flood.The ⁴He/²⁰Ne and ³He/⁴He of the oil from the Huangshatuo oil field were larger than those of air and they have a better liner relation,indicating they can be used for tracing water flood and its degree of an oil bed in a production well.