98.3%。This paper proposed a method for corn-weed recognition by using the combinationtechnique of image processing and support vector machine (SVM). A gray processing algorithm was proposed based on the features of corn-weed color images. The object could be separated effectively by denoising the gray image. The shape features of the object were extracted and taken as feature vectors, which could be used to propose the SVM method for the recognition of corn-weed. Comparing the SVM method with the neural-network one, the former is better than the latter one seeing from the experimental results. Experimental results also show that the presented method is effective, and this method gives a recognition rate 98.3% with the properly selected kernel function. 