Abstract: With the problem of partial seedlings of Pinus sytvestris var. mwngolica appear purple-red during growing seedlings in arid desert area, this paper has conducted the comparative research on soil properties of the plant nursery normal seedlings place and the purple-red seedlings place. The results show that, the main reason for the area Pinus sylvestris var. mongolica seedlings change to purple-red is that soil lacks for phosphorus. The low phosphorus land partial seedlings grow normally are because this place the soil sand content is high, the permeability is good, microorganism is active, these are all advantageous to the seedlings root absorb phosphorus.