论述了在土壤水分时空变化动态分析中采用回归等值线图的依据和原理。图的做法是先求出以深度和时间为自变量，以水分观测值为因变量，包括一次交互项的二元二次及二元三次方程，再依据方程进行绘制。根据方程的复相关系数及已有的经验选用其中一个图形。对两个示例进行了较为详尽的分析，可看出该图具有信息量大、醒目直观、便于分析等优点 The basis and principle of using regression isogram in the dynamic analysis of spatio-temporal changes of soil moisture are discussed. The approach is to find the binary quadratic and binary cubic equations with depth and time as independent variables and moisture observations as the dependent variable, including an interactive term, and then plotted according to the equation. According to the equation of the complex correlation coefficient and the existing experience choose one of the graphics. The two examples were more detailed analysis, we can see that the map has the advantages of large amount of information, eye-catching intuitive, easy to analyze