Abstract Aiming to solve the problem of crop yield forecasting and accurate fertilization, this paper presents a method based on optimized design ideas about fertilization decision-making. The algorithm is based on a variety of fertilizer function fittings, and weighting optimal solutions to obtain the fertilizing amount. The algorithm in this paper which uses the interpolation algorithm improves the rationality and reliability of fertilization by solving the problem of which need large-scale test, and large computation so as to become difficult to implement. This algorithm is composed of three sub-programs. One or some of its sub-programs can be used flexibly. The goals to access better economic efficiency with less inputs can be achieved.