Both China and US have both 资本主义 and 社会主义 components,

just different proportion.

Capitalism component is letting market/capital arrange resources (people, material, money). Capital wants maximum profit, resources go to most profitable industry/companies. So usually capitalism results high efficiency. But not very high in fairness, specially for people without capital.

Socialism component is that society forms organization (usually government) to arrange resources, usually according to the benefit of the whole society. It has better fairness, but usually not high in efficiency, no matter in China or US.

US governments collect 28.3% (don't know which year) of GDP as tax, so US is 28.3% socialism, for now.