Thanks for Paul leader's reply.
When we discovered it from its back, I tried to go in front of it. After I used my torch in front of it for 1 min, I flew away. But we can see clearly of its face and the throat.
Clearly, we cannot see a eye-brow on its face. Also, The first impression of it was a kind of Robin and may be a female siberian blue robin(?). But, when we looked at its eyes, it had big eyes without a obvious eye-ring and its face was evenly pale brown in color. On the other hand, the upper part of ots tail was not blue but brown, so it must not be a female siberian blue robin. So, it must be a kind of flycatcher.
I know this is difficult to tell the real size from the photo, but it could not be a warbler because it has no eye-brow.
And the color of this photo is a bit to bright.
Thank you very much
