What gift should I bring to my girlfriend when I come to Chengdu to play? She is a mature type.

I think if you want to bring gifts to your girlfriend when you travel abroad, then you can bring some special gifts from that place. Since your girlfriend is mature, I don't think you need to care about this. Gifts are mainly given according to your mind. If your girlfriend really loves you, then she won't care about the price of this gift. So if you want to give your girlfriend a gift, you can choose a special necklace, or some famous local jewelry, or some famous local decorations. Your girlfriend will be very happy to receive it.