Academic publications of latest research results are crucial to advance the development of all disciplines. However, there are several severe disadvantages in current academic publication systems. The first is the misconduct during the publication process due to the opaque paper review process. An anonymous reviewer may give biased comments to a paper without being noticed because the comments are seldom published for evaluation. Second, access to research papers is restricted to only subscribers, and even the authors cannot access their own papers. To address the above problems, we propose Open-Pub, a decentralized, transparent yet privacy-preserving academic publication scheme using the blockchain technology. In Open-Pub, we first design a threshold identity-based group signature (TIBGS) that protects identities of signers using verifiable secret sharing. Then we develop a strong double-blind mechanism to protect the identities of authors and reviewers. With this strong double-blind mechanism, authors can choose to submit papers anonymously, and validators distribute papers anonymously to reviewers on the blockchain according to their research interests. This process is publicly recorded and traceable on the blockchain so as to realize transparent peer preview. To evaluate its efficiency, we implement Open-Pub based on Ethereum and conduct comprehensive experiments to evaluate its performance, including computation cost and processing delay. The experiment results show that Open-Pub is highly efficient in computation and processing anonymous transactions.