The invention discloses a 
system and a method for constructing a soil available 
phosphorus analysis model based on a 
satellite image, and aims to solve the problems that time and labor are consumed, the cost is high and accurate and comprehensive fertilization cannot be realized when the soil available 
phosphorus content is used for guiding fertilization. According to the invention, a Spearman 
sensitive analysis technology and a GA + BP neural network 
algorithm are adopted, a soil available 
phosphorus inversion model is established by applying 
matlab programming and GUI design, pixel-by-pixel fine analysis technologies are carried out by applying multiple parameters such as sensitive wave bands, sensitive 
wave band mathematical transformation and 
field soil sample acquisition data, quantitative analysis is carried out on available phosphorus of soil fertilization, and thus obtaining soil available phosphorus 
content distribution raster data of the target area before 
sowing; compared with a traditional method, the 
remote sensing technology is used for 
processing satellite image data, the 
Matlab technology is used for completing model construction, the GIS technology is combined for completing correlation and grid vectorization of 
reflectivity information and soil sample data and guiding fertilization prescription 
map making, the production cost can be saved, the production efficiency is improved, and the purpose of farmland protection is achieved.