To study the online quality control of electric pencil sharpener packaging production line in company A and to figure out the direction for improvement. 5M1E (Man, Machine, Material, Method, Measurement, Environment) analysis was conducted for the online packaging quality problems of the electric pencil sharpener packaging production line, using the quality analysis tools such as Pareto, cause and effect diagrams. It was shown that scratches on sharpeners were the major packaging quality problem, which accounted for 46.54% in the total failure rate. Furthermore, AHP was used in the project to analyze the causes of the scratches, and the weights of the factors leading to the packaging quality problems were calculated with Yaahp. The key factors causing scratches were determined based on the weights of all the factors, which were the non-standard operation process, lack of skills training, unskilled operation and weak quality consciousness. The major factors causing the packaging quality problems were found out by integrated application of 5M1E and AHP, which could point out the direction for improvement of online quality management of packaging production lines.