Finally: Install Windows 10 for Phones on Non-supported devices topic

99.99% success! I found this method at one of Chinese forum: http://www.wpxap.com/thread-822065-1-1.html

Same idea with RustyGrom’s thread:http://forum.xda-developers.com/show....php?t=3030105

I just did some important translation :

1. Install the Windows Insider app on your phone (you will need to have a store account configured)
2. Open Internet Explorer on your phone and navigate to upwp10.chinacloudapp.cn:7777, then a file will be asked for download, accept and run the file to install it.
3. Edit the settings for your phone WiFi connection to turn on the Proxy and set it to use upwp10.chinacloudapp.cn as IP address and enter 7777 for the port
4. Run the Windows Insider app and tap get preview builds
5. You will see Enroll page with two option: Insider Slow and Insider Fast, Do NOT join any one of them now, your's might be in English

6. Return to your WIFI setting and turn off Proxy
7. Go back to windows insider by using Back button of your Winphone, and it is time to choice Insider Slow or Insider Fast.

Make sure your phone has at least 300M system free space.