Thank you all. Here comes the summary.
1. RN of China so far only has 8 digits. RN in first week begin with 800. Later on the RNs begin with 9. but still 8 digits. (Three German RN shared here. two are 8 digit, one is nine. a little confuse)
2. Most RN around world (expect for China, + Maybe Germany) seems are 9 digits. I found a RN of Canada is 10892xxx as an exception, double confirming.
3. Except China mainland. the RN of rest world begin with 107 or 108. Only one 100 was reported from HongKong.