Abstract: In order to recuperate localization of classical algorithms, it is advanced for the first time that the idea that is named as "pruning bowstring and protecting branches" , and a kind of downright new constructing algorithm of MST is designed and achieved creatively base on the idea. The result of experiment and math proving indicates that the new algorithm is right, The result of experiment and analysis indicates that the new algorithm can prominently recuperate the deficiency of classical algorithm in some actual application field and possesses important value on theory and application.

Key words: Pruning bowstrings and preserving branches,MST,Constructing algorithm