About 5000 pieces of low-efficiency defective crystalline silicon (C-Si) solar cells are collected, inspected and analyzed, and a defect inspection and classification evaluation system for C-Si solar cells is established. The system which includes current-voltage (I-V) test, thermal imaging test, electroluminescence imaging test etc., can identify 16 kinds of defects. The system can give out detailed description and evaluation of these defects following the steps of "defect definition, testing feature, influience on performance, original mechanism, preventive action, value of repairing". The result will be helpful in improving C-Si solar cell production and repairing defective cells.