Charge mobility and charge traps are two important factors that affect performances of semiconductor devices. Here, the measurement techniques and correlation with polymer structures is reviewed. Common traps, such as oxygen, aggregates, long conjugation length subchains, and impurities are found to appear in conjugated polymers and their features are described. Charge mobility is highly sensitive to polymer morphology and chain alignment. Incorporating transport moieties on side chains can either enhance or reduce charge mobilities depending on their ionization potentials. The relationship between charge transport behaviors and chemical structures are also discussed.