Ok kiddo, do you know what spying is? Yep, that’s right, it's when people try to get secret information from someone or somewhere they are not supposed to.
Now, the US government has a group of people called the Central Intelligence Agency or CIA for short, and one of their jobs is to collect information about other countries to help keep America safe from harm.
One of the places they focus on is China, because China is a big and powerful country that the US wants to know more about. So, the CIA sends their agents, who are called spies, to try to gather information about China.
But wait! This is not as easy as it may sound. China is a pretty secretive country and its government does not like people spying on them. So, the CIA has to make sure their spies stay hidden and don't get caught.
The spies use many tricks to gather information such as talking to people, taking pictures, and even secretly listening to phone calls or reading emails. But they have to be really careful not to get caught, because if they do, they will get in big trouble, and might even face jail time.
So, in summary, American espionage in China means that the US government sends spies to gather information on China, to understand what they are doing, and make sure America is safe. They have to be very careful and secretive while doing this, so they don't get caught by the Chinese government.