The mono-layer BOM and multi-layer BOM trees are defined, and two of the basic algorithms of traversal of multilevel BOM are summarized as well,which are Recursive Search and Level Search. Based on the analysis of algorithms principles, and evaluating the calculating rate, percentage of using CPU and practicability of them, a kind of improved Traversal of multi-level BOM algorithms is proposed. It is applied in relational database with high calculating rate, lower percentage of using CPU and high applicability. The software implement of these algori-thms is also introduced in detail, and the results of its application show that these algorithms are feasible and effective.