how to reduce the space between figure number and caption

hi, thanks for the reply. It is tab, but I don't know how to fix it, any suggestion please? thank you!

You should be able to delete the tab character by selecting it and pressing Delete.

Or are you saying that the tab gets added automatically as you apply the Caption style? In that case, which type of numbering are you using? Standard caption numbering (References tab | Insert Caption)? Or paragraph numbering? Please elaborate.

thanks for the reply! the space seems come out automatically and the steps are as follows, any suggestions please? thank you! 

It is more normal to use the References tab>Insert Caption facility

If you want the Heading number to be included in the caption numbering, click on the Numbering button in the Caption dialog to display the Caption Numbering dialog and then check the box for "Include chapter number" and then select the style that is used to start the Chapters.

If you want to insert a tab after the caption number in the Caption control of the caption dialog, you must use Ctrl+Tab, otherwise, you can just use the space bar to have one space separate the text of the caption from the number.  If you do use a tab, the point at which the text will start will depend upon the tab stops in the Caption Style.