For other people reading this: guoguochang wants to use Person Tracking with the SR300. Officially Person Tracking can work on SR300 and R200. It is very rare for it to be used on SR300.
The only SR300 Person Tracking video that I know of is this one from Mike Taulty (who has also produced tutorials on his blog ( https://mtaulty.com/ ) that have been very useful for other aspects of RealSense programming).
guoguochang would like to know how to adapt the R200 sample's code to work with the SR300. It was unfortunately something I could not help with - perhaps another member of this community could help.