Yingli is one of the leading vertically integrated photovoltaic (PV) product manufacturers in China.

Yingli, through its principal operating subsidiary in China-Baoding Tianwei Yingli New Energy Resources Co., Ltd. designs, manufactures and sells PV modules, and designs, assembles, sells and installs PV systems that are connected to electricity transmission grids or those that operate on a stand-alone basis.

Yingli is currently one of the largest manufacturers of PV products in China as measured by annual production capacity, with an annual production capacity of 200 megawatts of polysilicon ingots and wafers, 200 megawatts of PV cells and 200 megawatts of PV modules, as of July 2007 .

Yingli is one of the few large-scale PV companies in China with a vertically integrated  business model.  Its products and services substantially cover the entire PV industry value chain from the manufacture of multicrystalline polysilicon ingots and wafers, PV cells, PV modules and PV systems to PV system installation. Its end-products include PV modules and PV systems in different sizes and power outputs.  Yingli sells PV modules under its own brand name, Yingli Solar, to PV system integrators and distributors located in various markets around the world, including Germany, Spain, China and the United States.

Yingli has completed various large projects in Europe and China over the past few years, such as the China National Brightness Project in 2002. It cooperated with Solar-Energiedach GmbH NL in the design and installation of a 1MW PV system covering the roof of the Kaiserslautern soccer stadium in Germany, one of the 2006 FIFA World Cup  venues. At the end of 2006, Yingli signed a 42MW contract with Acciona Energy to help build the world's largest solar plant in Moah, Portugal.