Abstract: Photorespiration involves oxygen uptake and CO₂ release in light. The photorespiration of C₃ plants may consume 25% of the carbon fixed by photosynthesis, so engineering photorespiration could improve photosynthesis. Screening and use of photorespiration mutants is the best way to study the metabolism and functions of photorespiration. This review covers the research progress in selection and use of photorespiratory mutants for clarifying the metabolic pathway and functions of photorespiration.