SCTP used multiple stream to transfer single file
Only if you program it that way. It would be more correct to say that a single SCTP connection can contain multiple streams, unlike TCP which only contains one.
then TCP
Eh?
But one question raised that if SCTP transfer single file in multiple stream that will increase the traffic on that server then TCP
No, because the file is still the same length.
because TCP use Single Stream to transfer file?
The file is the file. It contains a fixed number of bytes. It's the same amount of traffic regardless of how you transfer it, unless you're asking about SCTP and TCP packet overheads, which you haven't stated.
Your question could do with considerable clarification.