This expression is used as "Excuse me" would be used when you want to ask some question. This expression will hopefully let you get the attention of the person you wish to ask something.
Check out this group of Chinese phrases too. You might find more useful Mandarin phrases. The current Chinese phrase "Excuse me" appears in this group
Learn how to say the Chinese phrase for Excuse me with standard Mandarin pronunciation. Free Mandarin phrases with pinyin and literal translation