1. A device for performing morphological analysis for erythrocytes, comprising: a: an automatic microscope, wherein a low-power objective lens of the automatic microscope is configured to scan a sample in a set area and to mark a found target area, and meanwhile a high-power objective lens of the automatic microscope is configured to scan the marked area; b: a camera or a Charge Coupled Device (CCD) element, which is configured to collect information of an image of the marked area; c: an image-digital converter for analyzing and processing the image, wherein the image-digital converter is configured to segment and position cells contained in the collected image collected at first, and then to digitize the segmented image to extract four types, including size, shape, chromaticity and texture, of morphological feature parameters of each of the cells; d: a classifier established on the basis of a neural network, wherein the classifier is configured to classify the cells according to the four types, including size, shape, chromaticity and texture, of the morphological feature parameters of each of the cells, obtained in the above step, so as to isolate erythrocytes from each type of the cells; e: a feature fusion device established on the basis of fuzzy clustering, wherein the feature fusion device is configured to perform normalized dimension reduction on the four types, including size, shape, chromaticity and texture, of multi-dimensional morphological feature parameters of the erythrocytes, which are isolated in the above step, to obtain four feature values of size, shape, chromaticity and texture, and then to perform statistical calculation and statistical graphic expression respectively according to size, shape, chromaticity and texture features of all erythrocytes in a specimen to provide real objective basis for analyzing type and source of the erythrocytes in the sample; f: an output apparatus, which is configured to intuitively display a detection result; and g: a control unit, which is connected to the automatic microscope, the camera or CCD element, the image-digital converter and the output apparatus respectively to control actions of the automatic microscope, the camera or CCD element, the image-digital converter and the output apparatus.