Abstract: In soils with different grassland plant communities. the activities of urease, phaphatase and celluase were in the order of A. chinense community > Calamaguostis elegies community > Puccinellia tenuiflora community> C. virgata community> Suaeda glauca community> alkaline spot; and dehydrogenase activity was in the order of C. epigeios community > A.chi nense community> C.virgata community> P.tenuiflora community> i community >alkaline spot. The temporal dynamics of urease, phaphatase and Celluase activities was parabolas in shape, the maximum in August and the minimum in June or October. The dehydrogenase activity reached the highest value in June, and the lowest value in October. Interrelated analysis showed that soil factors affecting urease activity were total N>Organic matter > soil unit weight > total P > pH; for phaphatase. were total P >organic matter > pH> total N > soil unit weight; for dehydrogenase were total N >organic matter> total p>soil unit weight > pH; and for celluase, were total N > organic matter > total P > pH > soil unit weight. The enzymic activities were gradually strengthened with increasing biomass, but the correlation between dehydrogenase activity and microorganism biomass was not obvious.

Key words: Soil enzymic activities, boil factors, Aneurolepidiun chinense grassland, three-dimensional fluorescence spectra, infrared spectroscopy, nitrogen deposition, soil solution, dissolved organic matter