I would currently classify China as a one-party socialist state under Communist Party rule with a state-directed mixed-market economy. Under Mao Zedong, China was a relatively faithful adherent Marx's writing and vision for communism, and I would classify it as communist one-party state with a highly collectivised, state-directed command economy.
The tricky thing about governing and economic systems is that they're never ideologically pure. No previous system can ever be called "purely" communist, nor can any current system be called "purely" capitalist. We therefore often analyse outcomes from nations using the dominant system is the lens.