The effective supply of phosphorus in paddy soil in red soil area is the key to ensure the high yield of rice. Soil phosphorus availability is closely related to the transformation of phosphorus forms. However，the changes of inorganic phosphorus forms in the key growth period of double cropping rice under different fertilization and its relationship with rice phosphorus utilization efficiency are still unclear. Based on the long-term experiment of combined application of organic fertilizer and chemical fertilizer since 1982，control(CK)，single application of organic fertilizer(M)，single application of chemical fertilizer(NPK)and combined application of organic fertilizer and chemical fertilizer(NPKM)were selected. This study monitored the changes of inorganic phosphorus components and phosphorus utilization rate in the key growth period of double cropping rice，and analyzed the correlation between them. The result showed that there were significant differences in the total amount of inorganic phosphorus among different treatments at different growth stages(NPKM>NPK>M>CK，P<0.05). The change of total inorganic phosphorus after fertilization mainly occurred in tillering stage and full heading stage. The contents of Al-P，Fe-P and Ca-P in NPK and NPKM treatments were significantly higher than those in M and CK treatments at different growth stages of early and late rice(P<0.05). The average contents of Al-P，Fe-P and Ca-P in the late rice growing season of each treatment were higher than those in the early rice growing season，with an increase of 4.6%-19.8%，0.2%-8.6% and 3.4%-23.3%，respectively. The average content of O-P in the late rice season of each treatment was 8.4%-35.0% lower than that in the early rice. The change trend of the proportion of inorganic phosphorus components to total inorganic phosphorus in early rice season and late rice season was the same among different fertilization treatments. The order of the average proportion of Al-P，Fe-P，O-P and Ca-P to total inorganic phosphorus in each treatment was NPKM>NPK>M>CK，M>CK>NPK>NPKM，CK>M>NPK>NPKM and CK>M>NPK>NPKM，respectively. The grain yield and phosphorus uptake of early and late rice increased significantly with fertilization(P<0.05). The rice yield and phosphorus uptake of MPKM were significantly higher than those of NPK and M treatments(P<0.05)，with an increase of 25.1%-33.3%，but there was no significant difference in phosphorus utilization rate between different fertilization treatments. The relative importance of Al-P and Olsen-P content in the vegetative growth period of early rice to the yield and phosphorus uptake of early rice was more prominent，while Fe-P in vegetative growth period and Al-P in reproductive growth period were more important to yield and phosphorus uptake of late rice. In the case of combined application of organic and inorganic fertilizers，it is necessary to optimize the amount of phosphorus fertilizer and strengthen the regulation of phosphorus fertilizer at tillering stage and full heading stage of early rice and late rice to improve the utilization efficiency of phosphorus fertilizer.