In the process of maize breeding, yield tests and the improvement of maize production and the examination, including the measurement of the length, diameters, row numbers, grain numbers per row and grain numbers of ears, is necessary. However, manual examination utilized for a long time not only needs to spend a lot of manpower and resources, but also has many problems, such as high labor intensity, low efficiency of observation and the nonobjective and inaccurate results caused by human interference, greatly limiting the speed and accuracy of the operation. Therefore, an automatic equipment of examination with the machinevision was presented. The colour images of singleface characters of maize ears were obtained by industrial cameras through USB. Then the model |B-R| and (G+B)/2 were respectively applied to gray the colour images. After that, the method of segmentation of onedimension maximum entropy was used to achieve binaryzation, obtaining binary images of contours and features of ears separately. Moreover, these two kinds of images were corrected automatically by the calculation of angles of ear contours of binary images. Based on the calibration of cameras, the unit pixel corresponding to the actual value could be gained and then the length and diameters of ears could be calculated. In addition, the width of rows of ears could be got by the scanning of points of horizontal black background and correction of scanning curves, according to the extraction of local features of binaryzation images. The number of rows of ears could be obtained by the modified model of numbers of rows. Furthermore, by the extraction of binaryzation images of local features of single line of grains, the number of grains of rows could be obtained, based on the scanning of the points of black background and its modified curve. Finally, the total number of grains of ears could be computed by the numbers of rows and that of grains in single row. The experimental results showed that the average accuracy of measurement of ear length and ear diameter were 98.05% and 97.99%; the correct rate of measurement of row numbers was 95%; the average measurement accuracy of the number of grains per row was 96.29%; and the average accuracy of measurement of grain numbers was 95.67%. Furthermore, Ttest was conducted to compare the difference with the standard value, demonstrating that there was no significant difference and the equipment was of reliability. The average speed of measurement of the whole ear was less than 600ms per ear, and the measurement speed of the test system was within 6s per ear, meeting the requirement of the automatic equipment of examination. This research provided the basis of equipment and technology for the modern seed industry, even for the development of agricultural information technology.