In order to investigate expression patterns of OsAMT in rice, a preliminary qualitative study was carried out on expressions of OsAMT1.1, OsAMT1.2, OsAMT1.3, OsAMT3.1, and OsAMT4.1 in rice shoot and root, and their respective expression levels except for OsAMT3.1 in rice root in response to 1 mmol/L NH₄⁺ or lmmol/L NO₃^- supply with the fluorescence RT-PCR technique for the first time. Results showed that expression of OsAMT3.1 was mainly confined to shoot, so it was presumed that OsAMT3.1 was insignificant to root NH₄⁺ uptake; expressions of OsAMT1.1, OsAMT1.2, OsAMT1.3 and OsAMT4.1 were found in both root and shoot; among the four genes detected, OsAMT1.1 was significantly higher than OsAMTI.2, OsAMT1.3 and OsAMT4.1 in expression level in all the three N treatments, so it was held that OsAMT1.1 contributed most to NH₄⁺ absorption in root; the expression level of OsAMT1.2, OsAMT1.3 and OsAMT4.1 were significantly suppressed after the application of NH₄⁺ or NO₃^- slight variation of gene expression could be detected with the fluorescence RT-PCR technique; it was found that the expression of OsAMT1.1 decreased slightly after N application, and that the effect of NH₄⁺ on down regulation of OsAMT1.1, OsAMT1.2 and OsAMT4.1 was slightly stronger than that of NO₃^- and it was the other way around in the case of OsAMT1.3. These variations could not be detected with the semi-quantitative RT-PCR or blotting method.