Hi
i have 3 point (A<--> B<--> C) and bandwidth between A--B is 60Mbps and bandwidth between B--C is 70Mbps
but maximum bandwidth between A--C is 10Mbps
all point use sxt lite 5 and wds is enbale
what's my problem?!

Use station bridge instead of WDS and see what your results are

Did not change anything

B is repeating link from a to c thus the low bandwidth of 10mbps at c .