Connecting flight to US

I'm from Philippines and I have to attend a training in US, i already have my visa, but my employer wanted me to travel on a connecting flight from Manila to China to New York, because it's less hassle on my part, so i wanted to know if i still have to get a chinese visa or an entry clearance, although i'ts just for my connecting flight and i won't go out of the airport. I tried to call the telephone given on their website, Visa Section: Inquiry: 0063-2-8482395 but it just keep ringing and no one answers. I would gladly appreciate your answer on my inquiry, thank u so much..