The large energy consumption and the associated carbon emission of the Bitcoin blockchain operations are growing to a non-negligible problem that could potentially undermine the sustainable efforts of many countries around the world. In this paper, we make the first and original attempt to investigate the carbon emission flows of the Bitcoin blockchain operations in China under different carbon policies with a Bitcoin blockchain carbon emission (BBCE) model. We find that without any policy interventions, the annual energy consumption of the Bitcoin blockchain in China is expected to maximize in 2024 at 296.59 Twh and generate 130.50 million metric tons of carbon emission flows correspondingly, which would exceed the annualized greenhouse gas emission level of the Czech Republic and Portugal in 2016. Moreover, the maximum carbon emission per GDP of the Bitcoin industry is estimated to reach 10.77 kg/USD in June 2026 based on benchmark assessments. In addition, policies that induce changes in the energy consumption structure of the mining activities may be more effective than intuitive punitive measures in limiting the total amount of carbon emission in the Bitcoin blockchain operation. In particular, we find that market access policy has an incentive effect on the emission reduction of the Bitcoin industry. After evaluating the policy effectiveness, we provide some novel insights for the sustainable operations of the disruptive blockchain technology by analyzing the carbon emissions pattern of the Bitcoin blockchain.