The identification of blood-secretory proteins and the detection of protein biomarkers in the blood have an important clinical application value.Existing methods for predicting blood-secretory proteins are mainly based on traditional machine learning algorithms,and heavily rely on annotated protein features.Unlike traditional machine learning algorithms,deep learning algorithms can automatically learn better feature representations from raw data,and are expected to be more promising to predict blood-secretory proteins.We present a novel deep learning model (DeepHBSP) combined with transfer learning by integrating a binary classification network and a ranking network to identify blood-secretory proteins from the amino acid sequence information alone.The loss function of DeepHBSP in the training step is designed to apply descriptive loss and compactness loss to the binary classification network and the ranking network,respectively.The feature extraction subnetwork of DeepHBSP is composed of a multi-lane capsule network.Additionally,transfer learning is used to train a highly accurate generalized model with small samples of blood-secretory proteins.The main contributions of this study are as follows:1) a novel deep learning architecture by integrating a binary classification network and a ranking network is proposed,superior to existing traditional machine learning algorithms and other state-of-the-art deep learning architectures for biological sequence analysis;2) the proposed model for blood-secretory protein prediction uses only amino acid sequences,overcoming the heavy dependence of existing methods on annotated protein features;3) the blood-secretory proteins predicted by our model are statistically significant compared with existing blood-based biomarkers of cancer.