VPN Routing question

I would like to create a VPN tunnel btw China and HK
In HK, I am using ADSL with dynamic IP (but seldom change)
In China, I am using ADSL but that is a share IP in the building, so I don’t have public IP address in my router.

In HK, I had setup a PPTP server and I can connect the pptp from china, and set some IP through HK VPN to route, like youtube.
in hk, the internal IP (192.168.100.0/24), in CN ( 192.168.200.0/24)
and assign the IP in 192.168.100.10 for CN pptp connect IP,

so in my HK’s pc, I can ping 192.168.100.10 and 192.168.200.1(router interal IP in CN) after I setup a route in HK router
my Question is is it possible I route my HK traffic through CN router? or how can I do it?
I don’t know why I cannot ping CN’s pc in my HK’s PC but I can ping HK’s PC in CN’s PC