输变电工程造价管理是电力工程建设管理的重要内容，为了在输变电工程建设决策、工程评审中提供一种定量的分析依据，定义包含期间内80%样本工程的区间为造价合理区间。提出了一种基于切比雪夫不等式的区间计算方法，该方法运用的箱线图优化了原始数据，提高了计算可信程度；然后依据切比雪夫不等式确定了寻优迭代计算的初值，利用一维寻优计算的进退法计算得到造价合理区间。计算结果具有一定的数学基础，可为电网工程标准化建设提供可靠的分析依据。

The electric power engineering cost management is an important content of power engineering construction management. In order to provide a quantitative analysis basis of project decision-making and project evaluation, a reasonable project cost interval that included 80% period samples was defined. An interval calculation method based on Chebyshev’s inequality was presented, which optimized the original data with using boxplot, to improve the credible degree of the calculation. The initial value of optimization iteration calculation was given based on Chebyshev’s inequality and the reasonable cost interval was calculated with using a one-dimensional optimization method called advance and retreat method. The calculation results have certain mathematics basis and can provide a reliable basis for the analysis of power grid project standardization construction.