Abstract: In order to solve limitations of both leaf-by-leaf measurement and oblique distortion of digital image, this paper presents a multi-leaf area measurement method based on geometric correction with rectangular box (GCCA for short). The method extracts rectangle box using Hough transform, carries out geometric rectification, and enables Multi-leaf simultaneous measurement using connecting regions scan. At the same time this method is carried out by Visual Basic 2010 programming, and be compared with grid method, length-width method and Photoshop method respectively. Experimental results indicate that the GCCA method is a high stability method with great relevance to grid method and a broad applicable scope. Inheriting the advantages of digital photography image processing method, the GCCA method is also a rapid method for measurement of plant leaf area and its measurement speed increases as the number of leaves increases in a single image. Compilation of the software can eliminate the influence of human factors, and greatly improve the interactivity and versatility of leaf area measurement. GCCA method can be both applied to indoor and non-destructive measurement outdoor, providing a practical new approach for leaf area measurement.