Abstract: This paper presents a new idea to determine polynomial ionosphere model with the circumstance that lacking of real observation data in special region. Besides real observation data, grid data calculated by global ionosphere model has been used as a background. The weight of two kinds of data has been discussed, and then mathematical model has been established. Secondly, the model continuity between two segments have been discussed, and then a smoothing method to calculate ionosphere delay has been studied, which uses two groups of time weighting neighbored model coefficients. Finally, the availability of the model was proved by mathematic experimentation.