Organic solar cells (OSCs) have attracted an extensive attention due to their light-weight, low cost and flexible features. Exploitation of novel polymeric donating materials is one of the mainstreams in the field. To date, a variety of conjugated polymers with excellent electron-donating properties have been developed. Based on these materials, power conversion efficiency of OSCs has reached to 9%. This review classifies these materials based on the chemical structures of the repeating units, and summarizes their progress accordingly. A number of representative materials, which have received much attention, are highlighted from the aspects of designing strategy, properties, device fabrication and performance. It is anticipated to penetrate more deeply the basic relationships among the chemical structure-packing structure-property, which could provide valuable information for the future materials exploitation.