In this paper a new computation scheme of the expansion of Chebyshev polynomials in irregular grids is proposed. It is an extension of the previous scheme proposed by Zhou. This scheme could adapt itself to complex change of data and is more useful to the weather analysis and forecast than the previous one. In this paper a new computation scheme of the expansion of Chebyshev polynomials in irregular grids is proposed. It is an extension of the previous scheme proposed by Zhou. This scheme could adapt itself to complex change of data and is more useful to the weather analysis and forecast than the previous one.