Dear JMH and C.Coulet,
Thank you very much for your help!
I have run my case using the keyword "STOP IF A STEADY STATE" and "ZERO DEPTH" successfully after about 10 hours with the suggestions you provided, I got the more realistic waterdepth finally, which is under the help of both of you. I don't know how to express my thanks. You are the experts of TELEMAC2D, yesterday I borrowed a book(Free Surface Flows) written by JMH from our library, which exited me so much.
Thank you so much!
Best regards!
yajuan