Public ownership is the principle aspect of their economy, and a working class party has domination over their state. The large firms and key industries are overwhelmingly publicly owned, with massive state owned enterprises forming the backbone of their economy. Private, cooperative, and joint-stock ownership covers mostly the small and medium firms, and the larger of these are heavily controlled and influenced by the CPC.

As for being "mixed," all economies are mixed, that doesn't mean we can't identify what the principle aspect of the economy is. Socialism isn't a "pure" mode of production, and neither is capitalism, you don't have X% capitalism, Y% socialism, etc. That's not how modes of production work.