In order to complete the basic operation in abstract data type of Child-Sibling Tree and then better serves for teaching and daily application, the paper solves a important and complex operation of the lack of depth research in Child-Sibling Tree——searching parents node. By the means of mathematical techniques analysis that the time and space complexity of the algorithm are both O(n). It is known by excavating its potential that the algorithm has good application prospects in the place-name searching system.