Anyone know this character?Her real hair is long straight hair,She has black bunny ears and red stripped stockings and I heard she bring gun .

Ah, this is a bit tricky. The girl is Mami Futami from Idolmaster. But she's dressed up as a character called Shimakaze from the Kantai Collection, which is a very popular online card game in Japan.

Arigatou for your help Amaterasu-san!:)