Crude oil and loess soil from north Shaanxi Province were selected to study effects of oil on growth of plant seedling and soil respiration in this pot experimental.Two kinds of oil treatment

the spilled oil-polluted soil(SOPS) and the mixed oil-polluted soil(MOPS)

were designed with different oil contamination levels.Result showed that SOPS treatments had no effect on germination of maize(Zea mays L.)and alfalfa(Medicago sativa L.) but adversely affected growth of the two plants;Both germination and growth of alfalfa were affected severely in the MOPS treatments.Soil respiration was sensitive to oil pollution

and increased with oil pollution rates.Although inhibition of oil contamination and some fluctuation since one week after oil treatment

soil respiration of all oil treated soils gradually went stable and had been significantly(p=0.05) greater than the control by the end of the experimental.The results indicated there were tolerant microbial species in loess soil.