I am trying to get different JSON from bitcoin market RESTful API. 
Here is the problem:
I can only send my single GET request to API one by one, so that I cannot get all the data from all the bitcoin market at the same time.
Is there a way to use Python thread(each thread send GET request using different client ports) to get multiple data simultaneously?
Yes.
Use threading for concurrent network requests.
If you do computations on the response you will be bound by the GIL (Global Interpreter Lock) in which case you can start other processes to do the computations on the data using the multiprocessing library.
Requests lib supports threading and Doug Hellemans "Python Module of the Week" blog posts and book are a great place to read and understand the Apis for threading and multiprocessing in python.
Send Multiple GET Requests to Server:80 port Simultaneously