It depends on the field of science.
China is is ahead in some special environmental and green technologies as well in some medical sectors. Furthermore China is producing many technlogical products for US companies and the US market. So may the US has the patents, but the Chinese have the know how to produce.
Certainly the US is leading in several fields of science, but Chinas population is 4 times bigger and so has more scientists and will evolve faster.
In addition China has the highest Pisa-Ranking in education. So the young Chinese generation contains not only more people, but also smarter people than in the US.
Now Chinese students cannot only read Chinese but also foreign books and so gather more information and knowledge to convert into new science, while the majority of the Americans only speaks one language and lacks the ability to read foreign books.
Traditionally China was the most advanced nation in history. Gunpowder already was invented 1000 years earlier than in Europe and the indusrial revolution started in China in the 13.th century.
As consequence China is today very specialized on many fields. Furthermore the socialis reform caused that China today concentrates certain industries to each city, so there is one city focussing on the gas industry, another one on textiles, another one on computer chips etc.
Such specialization and concentration enables to share new knowledge within these circles pretty fast and keep productivity high.
I am very sure that the western world as well the Chinese government does not really know about all the science and inventions that has been made in China.