not really. in 117 AD, the roman empire controlled about half the total area of contemporary china (5 million km^2 vs 9.6 million km^2). the estimated population at this time was 70 million, two orders of magnitude off china's 1.4 billion today. the only way you could consider rome to have been "bigger" is to consider what fraction of the world's population fell within its borders. about 21% of the world's population lived in the roman empire versus china's 18.4% share today. [1][2]

edit: or did you mean china contemporary to rome haha? most relevant figures are for the han dynasty. area was 6.5 million km^2 in 100 AD, and population was 57.6 million in 2 AD, making the two empires roughly comparable in size.

[1] https://en.wikipedia.org/wiki/Roman_Empire [2] https://en.wikipedia.org/wiki/China [3] https://en.wikipedia.org/wiki/Han_dynasty