The design began with the Soyuz model that Russia sold to China. However, it has progressed considerably from the original. Shenzhou seems to be larger, has a much-upgraded support module, and all the equipment has been redesigned and replaced. China might be 40 years behind in manned space exploration, but if NASA doesn't get moving, China will catch up eventually and go ahead.
Unfortunately, it seems the US government will respond only to direct competition and won't get serious until there is a manifest threat. China could own the moon in 20 years.