The rapid development of brain-computer interfaces has made memory uploading, brain controlling of some basic functions of computers, and the treatment of diseases or disabilities like paralysis and blindness possible. However, human consciousness cannot be fully replicated. This paper analyzes why brain-computer interface (BCI) cannot completely replicate human consciousness via a literature review method from three aspects: the limitations of BCI technology, the non-replicability of consciousness, and the challenges of interdisciplinary integration. Research shows that technical issues such as low signal precision and data scarcity restrict its reliability, subjective experiences and nonlinear neural activities of consciousness are difficult to simulate by programs, and that decoding neural signals is not equivalent to reproducing consciousness. Existing theories of consciousness lack engineerable equations, so human consciousness cannot be replicated completely under current situation.