In large databases, lack of labeled training data leads to major difficulties in classification process. Semi-supervised algorithms are employed to suppress this problem. Video databases are the epitome for such a scenario. Fortunately, graph-based methods have shown to form promising platforms for semi-supervised video classification. Based on multimodal characteristics of video data, different features (SIFT, STIP, and MFCC) have been utilized to build the graph. In this paper, we have proposed a new classification method which fuses the results of manifold regularization over different graphs. Our method acts like a co-training method that tries to find the correct label for unlabeled data during its iterations. But, unlike other co-training methods, it takes into account the unlabeled data in the classification process. After manifold regularization, data fusion is doneby a ranking method which improves the algorithm to become competitive with supervised methods. Our experimental results, run on the CCV database, show the efficiency of the proposed classification method.