Abstract: Process planning is a continued improving and optimizing process, and reverse process knowledge, namely process failure knowledge which is experience of process improving measures where process quality problems occur in production, is quite effective to improve and optimize process solution. A process improvement approach based on process failure knowledge was proposed, it includes eight steps: identifying potential failure mode, analyzing potential failure cause, counting risk priority number N, proposing improvement action, counting risk priority number N’ after improvement, tradeoff improvement action, accepting improvement action and saving process improvement data. On the basis of Web-based process failure knowledge management system (process FMEA, failure mode and effect analysis), the relationships between process failure knowledge and product and process information was established so as to implement the information and process integration between process FMEA and CAPP(computer aided process planning), and achieve effective process improvement. An airplane structural part(main girder) was used to validate process improvement utilizing process failure knowledge. This approach provides an effective measure to actively other than passively improve process solution during process planning.