Hi thomas kuang,
Please take a look at the attached example. Although if you are using data binding it is better to perform search on the data and then make changes to the visual state of the tree.
Also you can take a look at the following articles:
All the best,
the Telerik team
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items