Honestly, at this point I think their population is closer to three times ours; though it's impossible to be precise at all, because death statistics are as illegal to report in mainland China, as any other politically sensitive thing.
We know for certain that their birth rate has been lower than one-child-per-woman and falling for the last couple of decades (and given their demographics -- most of the population being well past child bearing age for a woman -- this definitely implies that the population of domestically-born Chinese people has been shrinking), and we also know for sure that an abnormally large number of deaths went unreported or grossly under-reported in 2020, 2021, and 2022. (We've got satellite images of the backlog stacked up outside of crematoria for months at a time, and needless to say there's nothing in the official stats to correspond to that.) As for immigrants, expats have been leaving China like rats off a sinking ship for the last half decade or so. Estimates of the current population vary wildly; I've seen figures as low as half a billion, and as high as 1.5 billion; but realistically, I think on the one hand it's clear that there's been a significant decline, and on the other hand it's also clear that China is still significantly more densely populated than America. On the whole, I estimate that their population is about three times ours, give or take. And continuing to decline.
Whether this decline is altogether a bad thing (for China, I mean), is another topic for another day.