Hello tao jiang,
There can be two problems:
Either there is an issue with the log generation in GTS (could be due to some config) or the business partner did not transfer from ECC at all.
In GTS, my config uses profile MD_BP (Business Partner Distribution) & MD_BPM (for Business Partner Mapping). It shouldn't matter but can you give a try with this config?
Can you check if you have any custom coding in the transfer of data from ECC to GTS?
Thanks,
Satish