http://www.webpagetest.org/result/160801_VP_XHH/1/details/
what is the First Byte Time, how can I improve it (it looks like the DNS is taking too much time).
I am using CloudFlare Pro . and the VPS is in UK.
Try several runs to see if it is consistently that bad. Also check with cloudflare to see if they have DNS edges in-country. It’s possible that the dns may have been slowed/interfered with if it went through the great firewall. Multiple runs may mask any issues though since it may end up in server caches.
Your best bet for understanding if there is a real problem is to use something like Google Analytics or SOASTA mPulse and look at the DNS timings from your real users visiting from China (if you have any to the page).