So far actress Li Bingbing is the only Chinese actor cast for the film. However Ganis says, ""So much of the movie takes place in China and the character she plays is a Chinese national. So it's a very natural position for her to have." He also added that with Transformers 4 they are not going to have a China specific cut of the film (like with Iron Man 3, "There is going to be a single version (of the film) worldwide with a very significant Chinese component."
Taking his statements literally, it sounds like a majority of the film is set in China. This is fine if the story is good but the current filming reality seems to not match that stance. The core cast is not from China, the three to four months of filming is taking place in the United States, and a portion of Hong Kong set scenes are being filmed in Michigan. Considering most films (including the previous three TF films all took around 4 months to film, it doesn't seem to leave a lot of time for the China portion of the film if take the literal interpretation. I suspect what ultimately will happen is some event related to the story will take place in China in much of the same way that Revenge of the Fallen opened in Shanghai, China. The main difference is the TF2 scenes were filmed in Bethlehem, Pennsylvania and this time it will be the real deal. Considering how little China has a part in the average Hollywood blockbuster film, even a 10 minutes or so segment would be considered "significant." Below is a video of the interview. Thanks to Wynton R. for the links.