Active personnel: USA: 1,301,300 China: 2,300,000
Available for military: USA: 73,270,043 China: 385,821,101

China has more armored fighting vehicles (46,000 to 4,788) more artillery (9,726 to 3,269) more self-propelled artillery (1,710 to 950), more rocket artillery (1,770 to 1,197). And China has more tanks.

So China has a HUGE advantage on land.

On the oceans, China has more frigates (51 to 0), corvettes (32 to 0) and submarines (73 to 70). US has more destroyers (85 to 32).

USA still has the advantage in the air, with 12,100 aircraft to China's 3,729.
US has more multi-role aircraft: 2,062 to 567, more attack aircraft (470 to 300) and more helicopters (5,000 to 1,627).
But China has far more fighter aircraft, 1,199 to 388.

The one major advantage the USA has is having far more aircraft carriers. But with China having three times as many fighter aircraft, how long would it tale them to sink those carriers?