It means they are very good friends

In China you can see that many two girls walking arm in arm with arms in arms in campuses, in the streets,and in shopping plazas.

Walking arm in arm is a very common phenomenon between young girls in China.

Maybe At first maybe you will feel surprised that the girls are so open-minded.There are so many gay girls gays in China.

Please do not misunderstand.The two girls are not two lovers,not gays,but good friends.

Walking arms in arms means that they are very good friends!

In china if you are good friends you can carry hold arms in arms with your friends in any time.