In 2008, Satoshi Nakamoto proposed an electronic cash system (bitcoin) that is completely realized by peer-to-peer technology. The core value of this scheme is that it proposes a solution based on Proof-of Work, so that the cash system can run in a peer-to-peer environment and be able to prevent double-spend attacks. Bitcoin has been developed for ten years, and since then countless digital currencies have been created. But the discussion of double-spend attacks seems to still concentrate on 51% Attacks. In fact, our research has found that there are many other way to achieve double-spend attacks. In this paper, by introducing a number of double-spend attack vulnerabilities that we have found in EOS, NEO and other large blockchain platforms, we summarized various reasons for causing double-spend attacks, and propose an efficient mitigation measure against them.