Abstract: The paper describes the results of the research of the feasibility of pureinstrument multielement reactor neutron activation analysis with short timeirradiation. The experiments were done at heavy water research reactor ofInstitute of Atomic Energy, Beijing, China. Using two short time irradiations andthree measurements, we could determine thirty to thirty-six elements. The detec-tion limit of about thirty elements are below their average concentrations in theearth. This method is suitable for determining large amount of geological explora-tive and environment samples.