Tell can i use ubon u31 chinese earphones with iphone or not?

I'm using its working

You can use it but this is not the best option. For iphone you need to buy branded headphones. Branded headphones helps you to enjoy the real music experience.
As per my personal experience Panasonic headphone is the best option for music. This seems to be highly compatible with all types of mobile phone and IPOD.
http://www.panasonic.com/...hones.html

No they won't damage the phone and yes you can use it. But they won't sound so good. By the way. How can you ask so much questions.