The invention belongs to the technical field of scheduling management, particularly relates to a tree search-based same-sequence department decision process generation method, a tree search-based same-sequence department decision process generation system and a tree search-based same-sequence department decision process generation device. The invention aims to solve the problem of unstable optimization result caused by randomness of a same-sequence department decision process optimization algorithm in the prior art. The method comprises the steps of adopting an improved NEH algorithm to construct an initial solution set based on the obtained decision task number, department number and decision time of departments in the same sequence; performing forward and reverse search by taking the initial solution as a current node; judging whether the obtained forward and reverse sub-nodes are the same as the existing nodes or not, if so, stopping searching, and otherwise, comparing with the progenitor nodes in pairs; and if at least one pair is not equal, continuing searching, otherwise, outputting a corresponding decision process. According to the method, the initial solution set is constructed, the pruning step is added in the decision process optimization process, unnecessary search directions are eliminated, the decision optimization time of the algorithm is shortened, and the management efficiency and stability of departments in the same sequence of enterprises are improved.