Thank you very much.
I read his tutorial and know that seems I have to use .statOn and .paramOn to do something like SetOptStat and SetOptFit can do.
But It seems that in RooFit I can’t use the code like SetOptFit(1111) to display the stat like chisquare/ndf and so on (ps:the .statOn can induct the parameter like “What(“nemr”)”,but .paramOn cant induct “What(1111)” .
So Do I have to calculate the Statistics by myself and put them on the canvas in text?