During his reign as emperor of during 1260 AD to 1294 AD as a part of the Yuan Dynasty.
During this time he made a few changes but the three biggest were:
1. Infrastructure: Kublai Khan invested heavily in China's infrastructure, constructing extensive networks of roads, bridges, and canals that improved transportation and communication throughout the empire. He also built the Grand Canal, which linked the Yellow River and the Yangtze River and allowed for easier trade and commerce.
2. Cultural Exchange: Kublai Khan was interested in promoting cultural exchange between the various ethnic groups within his empire. He invited scholars, artists, and religious leaders from all over the world to come to China and share their knowledge and ideas. This led to a flourishing of the arts, literature, and science in China.
3. Economic Reforms: Kublai Khan introduced several economic reforms that helped to stabilize China's economy. He standardized weights and measures, which made trade and commerce more efficient. He also introduced paper currency, which replaced the heavy and cumbersome metal coins that had been used before. These reforms helped to create a more stable and prosperous economy in China.