First, in the 1850s, Chinese immigrants moved in large numbers to the US because they escaped the hard economic time in China. Britain defeated China in the Opium War, which occurred in the 19th century. Consequently, Britain’s dominance in Chinese economic affairs had adversely affected many Chinese nationals, and therefore they wanted to make more money and send part of it back to their poor families.
Secondly, they wanted to try their luck in the gold rush. Considering that they had left their poor families back in China, they hoped that this opportunity would transform their livelihoods and that of their families. Additionally, the US symbolized a great nation and a superpower full of opportunities, and such immigration would affect their lives positively besides the monetary gain.