My harp guitar get some trouble...
so.. I try to find some information about single string bridge..
but I can't find any information.
Please let me know web link or any information..
It's not just the bridge -- your top is lifting and your guitar needs repair. I'm MUCH more concerned with the exposed kerfing between the side and the top.

You need to get that thing to a really good repair tech.
when i think single string bridge i think of this schaller bridge i wanted a few years ago. But yes a good bridge makes the guitar sound good. Better tone , better intonation , less string breakage. Anything beats a small piece of zinc. Notice how I don't use the S word sustain because every single guitar part company mentions it and they are right most of the time if upgrading from a cheap chinese guitars hardware. but yeah.. this is a Schaller Hannes bridge.