Abstract: Lutetium oxyorthosilicate(LSO) is a new type of inorganic scintillator which has high scintillation efficiency and fast decay time. The properties of a current scintillation detector made up of LSO and PMT were studied. The sensitivity to incident gamma ray of different energy was measured by means of different methods. The sensitivity (ratio) of gamma to neutron is above 28 at least. The result shows this new type current scintillation detector is very appropriate for measurement of gamma pulse in a neutron-gamma mixed field.