I'm going to London next month and I want to visit Paris for only one day but I don't have time to get a Schengen visa so can I get it from the train station at Paris as I hold a UK visa ?
You will not be able to get a visa from the Paris train station as you will be unable to get on the train to Paris without entry clearance to France.
Having said that, some long-term UK visa may allow you to travel to the Schengen area. But according to the wording of the question, these rules are likely not to apply in your case.
You can check the visa requirements using Wikipedia. Type "visa requirements for citizens wikiedia" in your favorite search engine and follow the links. From the table that you will be getting, go the the "France" row and follow the link to the references. Then click on the reference again. You should now see a "timaticweb" URL in the browser address line. The page that you will be seeing then should list all the possible documents/visa types that allow you to enter France.