The top PCT applicants of 2009 include two Chinese providers of telecommunication and network solutions:
Rank 2: Huawei Technologies Co., Ltd.: 1,847 PCT applications published in 2009
Rank 23: ZTE Corporation: 502 PCT applications published in 2009
The Economist made a nice visual representation of those WIPO statistics, see here. You see that China ranks fifth, just behind the US, Japan, Germany and South Korea and before France, Britain and the Netherlands. The Economist wrote: "Since 2005 applications from China have grown by 210% as the country has developed a home-grown high-tech sector."
Domestic patent applications: According to WIPO statistics of 2008, China is after the US and Japan the third biggest receiver of domestic patent applications. Read more here.
The statistics of the number of PCT or domestic patent applications are interesting, but of course the number of patent grants are more interesting.