Researchers usually face difficulties in finding scientific papers relevant to their research interests due to increasing growth. Recommender systems emerge as a leading solution to filter valuable items intelligently. Recently, deep learning algorithms, such as convolutional neural network, improved traditional recommendation technologies, for example, the graph-based or content-based methods. However, existing graph-based methods ignore high-order association between users and items on graphs, and content-based methods ignore global features of texts for explicit user preferences. Therefore, this paper proposes a Content-based and knowledge Graph-based Paper Recommendation method (CGPRec), which uses a two-layer self-attention block to obtain global features of texts for more complete explicit user preferences, and proposes an improved graph convolutional network for modeling high-order associations on the knowledge graph to mine implicit user preferences. And the knowledge graph in this paper is constructed with concept nodes, user nodes, paper nodes, and other meta-data nodes. Experimental results on a public dataset, CiteULike-a, and a real application log dataset, AHData, show that our model outperforms compared with baseline methods.