Splash screen loading slow in China

I have an app having front-end and back-end, so, when I tested in the US, it loads very fast, but the Chinese users reported loading is very slow, like 30 seconds, it just stuck on the splash screen, at that time, I was using AWS to host my back-end. Then I thought it is server issue, I switched to Chinese server now, but the Chinese user is still reporting slow loading on splash screen. But the weird thing is my loading in the US is still fast.

I know it is not necessarily Ionic’s problem, but I just really need help since I am stuck on this for months, I changed so many servers. Could anyone point me the possible reasons or tell me how does Ionic splash screen works, what trigger the splash screen to hide ?

Thanks so much in advance for any points!

so I did some search, I found a possible reason is http://stackoverflow.com/questions/15528421/why-phonegap-deviceready-event-is-fired-after-a-very-long-time

is that true, when the app run, it will automatically connect to phonegap website? How can I disable it? where should i put the cordova.js locally ?