Abstract: The measurement of plant leaf area has great significance in the fields of agriculture and forestry. Traditional methods have disadvantages of long-period development, incomprehensive measurement, damnification crop, etc. An area measurement instrument for plant leaf has been developed applying LabVIEW 7.1 and general image acquisition card. The hardware structure of the instrument includes workbench, CCD camera, lighting, image acquisition card, personal computer; the software of the system consists of image acquisition module, image processing module, and image analysis module. From the result of test, it can be seen that the instrument has the advantages of simple operation, high efficiency, and nondestructive measurement.