In this paper, we propose a supervised dictionary learning framework for blind image quality assessment (BIQA) by using quality-constraint sparse coding. Different with the traditional dictionary learning framework which only ensures the learnt dictionary accounting for image features, we add a quality-related regularization term in the framework to learn a feature-related dictionary and a quality-related dictionary jointly. Specifically, the feature-related and quality-related dictionaries share the same sparse coefficients, so that the reconstruction errors form the image feature vectors and quality score vectors are both minimized. Once the feature-related and quality-related dictionaries are learned, given a testing sample, we first abstract its feature vector and then compute the corresponding sparse coefficients w.r.t. the learnt feature-related dictionary, its quality score can be directly reconstructed based on the learnt quality-related dictionary and the estimated sparse coefficients. Experiment results on three publicly available IQA databases show the promising performance of the proposed model.