An image processing circuit includes a receiving circuit, a feature fetching module and a decision circuit. In the operations of the image processing circuit, the receiving circuit is configured to receive image data. The feature fetching module is configured to use a multi-topological-convolutional network to fetch the features of the image data, to generate a plurality of image features determined by the characteristics and weights of the convolution filter, where the image features may be smooth features or edge features. In the present invention, the convolution filters used by the feature fetching module are not limited by a square convention filter, and the convolution filters may include the multiple topological convolutional network having non-square convolution filters. By using the multiple topological convolutional network of the present invention, the feature fetching module can fetch the rich image features for identifying the contents of the image data.