Abstract: The soil nutrient, soil microorganisms and soil enzyme activities of soil under five different stands in Alar were studied. The results showed that the soil nutrients, soil microorgamisms and soil enzyme activities of soil four stands are all higher than the Populus euphratica stands. But the Populus euphratica stands is of the strongest anti-salty. The number of soil microorganisms in five stands was increasing from April to August, there is a maximum in August and bacteria were predominant. The urease, catalase, alkaline phosphatase activities of soil were “increase in fall”. The maximum is in October, but the investase activities are opposite and the maximum is in April. There is close correlation between soil microorganisms and soil enzyme activities, soil nutrients.