The Tang and Song eras are not only known as being the "Golden Age" of China, rebuilding and centralizing the nation, but they are also well known for the advances in science and technology that occured. Some of these advances include gunpowder, missles, coal, kites, and the abacus.
In technology, there were great strides in conquering the geographiclly challenged nation. Bridges and canals were built, along with dams and better irrigation and farming systems and techniques. Some other inventions that impacted China and the surrounding civilizations were the compass (used in ocean navigation), the abacus (used as a calculator), printing (which made knowledge more widespread), and other things. Another important invention was gunpowder. Although this was originally used in fireworks (which is another invention), gunpowder had begun to find its place in war in the Song era.
Although these things did not reach much of the rest of the world at the time, it ultimatly affected the surrounding nations and many of these inventions formed the base of the technological knowledge of today's world.