The power conversion efficiencies (PCE) of polymer solar cells have now both reached over 17% for single-junction and multi-junction devices. However, in order the meet the commercialization requirement, further improvement in device stability and the exploration of niche applications of polymer solar cells are urgently needed. In this talk, I will discuss how to utilize an integrated strategy combining material design, interface engineering and optical management to tackle the efficiency and stability challenges of polymer solar cells. The molecular structures, crystal structures, thin film nanostructures, interface and device structures and their relationship to the overall properties of polymer solar cell will be discussed. I will also highlight how to apply high throughput optical calculation to guide the design of semitransparent and tandem polymer solar cells with state-of-the-art performance.