"Capitalism" means private ownership of capital. 30% of industrial and service sector assets in China are stated-owned:
http://blogs.worldbank.org/eastasiapacific/state-owned-enter.... About 45% of the industrial sector is state-owned, down from 70% in 1999 (still more than two decades after Deng left office, and more than a decade after China's economic boom began). The profit share of the state owned enterprises is even higher: 43% of industrial and business profits in China yield from state owned enterprises:
http://thediplomat.com/2013/06/19/reforming-chinas-state-own....
In a purely definitional sense, China is at best a hybrid economy now, and was a primarily communist economy long after its economy started booming.
Even to the extent that China's economy is ostensibly privately owned, the government still exercises tremendous control. For example while the banks are joint stock companies, and thus reflect substantial private ownership of equity, the Chinese government still owns the majority of the shares in many of them giving them tremendous power over those banks.
I don't think China can be fairly called a "capitalist" economy. It's a managed economy where the managers have allowed the free market to allocate resources at the lower levels, while the central government directs broader, longer-term economic objectives.