There is a problem when I set up my server system ,IP would be different when I use Wired network connection and wireless network connection，how can I set unchanging IP when I connect to the system? Thanks for your help.
The prior answer assumes you're talking about external IP address; which is set by ISP. I take your question as asking about the LAN IP address; which can be changed in many ways.
On my own ubuntu 16.04LTS (running XFCE so think Xubuntu) I can 'click' the network icon on top of my left monitor and view "Network Connections"; A dynamic (changing, or set by router) uses DHCP (d=dynamic) which just needs to be changed and you're done. You can do it this way if you prefer; using your current addresses as a guide. Keeping wireless as DHCP may be worthwhile (it'll likely work in more locations)