GNSS data can be used to inversely derive the theory and method of ionospheric spatial structure. Since the distribution of electrons in the ionosphere is significantly influenced by geomagnetic, solar radiation, crustal movement etc., this paper analyzes the characteristic of spherical-harmonic function which can reflect the characteristic of ionospheric spatial lay-distribution, and studies this Champan function which is an ideal model to describe distribution of vertical ionosphere. A new three-dimension SHCF model for tomography spacial ionosphere is established. Based on the height distribution of static subsolar ionospheric E layer and F layer, the constant parameters of the model are determined. The measured data from GPS CORS in Chinese region at September 4, 2008 is used to illustrate the new algorithm, and the estimated residuals of the algorithm in two time periods are 0.247 m and 0.196 m respectively. And its reliability and accuracy are further verified by the vertical density charts of different positions and the three-dimension distribution of the residuals. In addition, the residuals of different altitude angles computed with SHCF are compared to that of single-lay spherical-harmonic model. This new algorithm is not limited by priori conditions, so it has great application potentials.%利用GNSS数据反演电离层空间结构的理论和方法是近年来相关学者研究的热点之一。基于电离层中电子分布受地磁、太阳热辐射和地壳变动等影响较大，利用球谐函数能有效反映电离层空间面分布关系的特点，结合Champan函数是描述电离层垂直剖面密度的理想模型，建立了一种层析电离层三维空间结构模型-SHCF。根据电离层静日下E层和F层的分布高度，合理地确定了模型中的参数。以中国区域GPS CORS2008年9月4日两时间段的实测数据为例，计算出模型在两时间段内估计的残差分别为0.247 m和0.196 m；并通过不同位置垂直方向的密度分布图和三维残差分布图进一步验证了模型的有效性和可靠性；同时，对新模型与球谐单层模型估计后的残差受高度角的影响也进行了对比分析。由于该模型不受先验条件的约束，因此，具有较大的应用价值。
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