Beginning in the time of the California Gold Rush, and continuing until the ban on such immigration in the 1880s, many Chinese people came to the United States as immigrants. The bulk of them came as laborers. Their main identifiable contributions to American society were the fruit of their labor.
Chinese people made other contributions to the United States. Most notably, they have contributed their food to the American diet. Even very small towns in the United States today have Chinese restaurants. This is in part a result of Chinese immigration.
However, by far the greatest impact of the Chinese is the railroads on which they worked. The bulk of Chinese immigrants from the 1860s on worked on the railroads or in related jobs. The Chinese laborers did the most difficult and dangerous work as the transcontinental railroad was pushed through the mountains of California. Large numbers of Chinese workers died to create the railroads that helped to cause the economic boom of the late 1800s.
Thus, the greatest impact of the Chinese immigrants was the railroad system that they helped to build and which helped to make America’s economy industrialized in the late 1800s.