That is a very broad question. There are online directories that can list trade shows all over the planet for example http://www.expodatabase.com/ but if it is an exhaustive list, or if you'll find the shows that your company can benefit from I dare not say. 

Maybe another entry to this search would be to find you biggest competitor in the target market, have a look to see what trade shows they participate in. 

I know, I was born just beside one of the really big machinery company, which is also exporting to China Information are expensive in these days, so ... how much you pay me as intern ?