The discussion on whether quantum computing is sufficient to crack the Bitcoin encryption system has heated up again recently, The core controversy is not about whether it will happen, but about when. Some researchers have pointed out that quantum attacks pose a real threat to Bitcoin, or it may only be an engineering problem rather than a theoretical breakthrough. Once it happens, about 1.7 million early BTC may be the first to suffer due to exposed address structures, and the community will face a difficult decision between freezing assets or allowing them to be stolen. Even more tricky is that even if an anti quantum upgrade is initiated, the real cycle from scheme selection, consensus reaching to migration completion may take several years. Divergence is widening: some believe that the quantum threat is greatly exaggerated, while others warn that procrastination itself is the biggest risk. Parallel to the debate, more and more public chains have taken action in advance, incorporating anti quantum cryptography into their roadmap and conducting defense exercises from test networks, account layers to signature mechanisms.