在对现有文献研究的基础上，对适时性损失计算中作业期最佳分布定理及其证明方法又作了进一步探讨，指出了单项作业时作业期最佳分布定理的局限性，并对其进行了修正；同时对有两项关键作业时作业期最佳分布定理的证明方法进行了剖析，指出了其存在的不足，并给出了一种新的证明方法 On the basis of the existing literature, the optimal distribution theorem and proof method of working period in time loss calculation are further discussed. The limitations of the optimal distribution theorem of work period in single work are pointed out. At the same time, this paper analyzes the proof methods of the best distribution theorem of job period with two key tasks, points out its shortcomings and gives a new proof method