The effect of moisture conditions and oxalic acid (OA) co-application was researched on the transference and transformation of phosphorus from phosphate fertilizer in the fertisphere (micro zone between fertilizer and soil) of a paddy soil from Hubei Province, central China. The results showed that the amounts of water soluble P and Olsen P were significantly reduced with the incubation time increasing. The transference and movement of water soluble P and Olsen P could be promoted by flooding or co-application of OA. But the amounts of water soluble P and Olsen P were less in soil with flooding than that with the moisture of 60% of field water capacity. The amounts of water soluble P and Olsen P in the fertisphere of soil wetted to 60% of field water capacity were increased with the co-application of OA, but decreased when the soil was flooded.