Precipitation during spring season greatly influences the productivity of typical steppe in Inner Mongolia. However, little is known whether spring rainfall affects the turnover of soil microbial biomass phosphorus. In this study, a simulated spring rainfall experiment with three treatments of none rainfall (W0), a simulated rainfall of 20 mm (W1) and twice simulated rainfalls of 40 mm (W2) was conducted in April 2015 at Maodeng farm Xilinhot Inner Mongolia. The aim was to compare the characteristics of seasonal changes in soil microbial biomass phosphorus, and understand the impact of the simulated rainfall on soil microbial phosphorus turnover and its relationship with plant P nutrition. The results showed that: (1) the simulated spring rainfall significantly increased soil microbial biomass phosphorus (SMB_P). The annual average values of SMB_P increased from 6.91 μg/g at W0 to 7.47 μg/g at W1 and 8.29 μg/g at W2, respectively. In particular, the turnover time of SMB_Pin W2 was shortened to 0.53 year. The turnover flux enhanced to 33.16 kg hm^-2 a^-1, while W0 was 0.59 year and 26.82 kg hm^-2 a^-1 respectively. (2) The simulated spring rainfall generally induced a reduction in soil acid phosphatase activity, but an increase in alkaline phosphatase activity. (3) The simulated spring rainfall resulted in obvious increases of both plants above-ground biomass and total phosphorus content. However, weak correlations were obtained among the plant above-ground biomass or total phosphorus content with soil microbial biomass phosphorus, acid /alkaline phosphatase activity, and soil available phosphorus content as expected.Our results might imply that there was a complex relationship among soil microbial biomass phosphorus, soil available phosphorus, and plant phosphorus nutrient in typical steppe of Inner Mongolia. Soil microbial biomass could compete with grass on soil phosphorus and thereafter influence plant P nutrition.