Ancient China had started to contribute to the modern world with its inventions since 1600BCE. Their most contribution in terms of inventions was paper, compass, silk, gunpowder, and fireworks. Let me describe few which has positive contribution (skipping gunpowder and firewroks as these two had destructive impact)
Paper was their most impactful contribution, because it is still used today. Paper was once made very thick, until someone figured out a way to make a fine thin paper. First they cut dried bamboo, squash it into powder, mix it with water and then use a very thin slice of material to lay it on and let it dry.
Ancient Chinese paper was invented because the thick hard paper had taking forever to write on. Paper had made a contribution to the modern world because it is still used today.
The ancient Chinese compass was also another great invention. The compass was mostly a type of magnetic metal all around with a spoon like figure on top to point a direction. The Chinese first used the compass to help build the house to make it straight and in line together. The Chinese then figured a way to take the compass sailing with the sailors to give them directions on where to go.
Silk was an important fabric in ancient china. Silk was always traded from china to another country. Silk was made out of silk worms or silk cocoons. Many things like clothes, Chinese fans and kites were made out of this soft fabric. Many inventions that was made and mentioned was a worlds great contribution to the modern world.