提出了地基望远镜主镜在环境温度变化时的温度场理论模型，结合分离变量法和格林函数法求解出温度场的解析表达式。运用温度场理论解，分别以熔石英和BK7两种常用材料为例，在特定环境条件下,定量分析了传统主镜和薄主镜的主镜视宁度与主镜口径之间的关系；针对4 m口径的传统主镜和薄主镜定量分析了其主镜视宁度与周围空气温度下降斜率的关系。地基望远镜主镜温度场理论计算的结果在主镜设计阶段对主镜视宁度的估量具有较大的参考价值。主镜温度场理论解还可以运用于各种口径及材料的主镜热变形及热应力计算等方面，具有普适的参考价值。

A temperature field theoretical model of classical telescope primary mirror is presented. Analytical solution is gotten by separation of variables and Green′s function method. It is easy to get the temperature difference between primary mirror work surface and ambient air with the analytical solution of the temperature field. A quantitative analysis of the primary mirror seeing is addressed. The relationship between primary mirror seeing and the size of primary mirror is studied in two different materials (fused silica and BK7) and two different kinds of mirror (traditional mirror and thin mirror) in two definite conditions with analytic solution. For 4 m traditional mirror and thin mirror, the relationship between primary mirror seeing and descending slope of the ambient air temperature is also presented. The quantitative analysis is helpful for estimating primary mirror seeing. The analytical solution of primary mirror is also valuable in designing telescope primary mirror for calculating thermal stress and thermal strain.