A new method called cornering method is provided in this paper.Based on result of draw-out simplification algorithm,length constrained method realizes minimized change of length property of 2-D geo-line features within reasonable shape and position accuracy.Cornering method improves accuracy of geo-line features length property,so that geo-line features processed by cornering method have higher degree of accuracy and credibility for applications like online statistics and real-time analysis of length property of geo-line features.