China has launched a national level carbon emissions trading market with a rate-based cap and benchmarks in the power generation sector. This emissions trading system (ETS) differs from a mass-based one, which lacks an absolute carbon cap. This study assesses the impact of such an unconventional ETS on economic development, carbon emission mitigation, and power system transition by applying a multi-regional dynamic computable general equilibrium model. The results show that ETS can facilitate the decarbonisation of the power sector and reduce carbon intensities of coal and gas power, the two technologies covered at the first stage of China's ETS. Furthermore, power generation of these technologies will be decreased significantly, and a noticeable fallback of electrification will occur. National GDP loss under a rate-based cap is slightly higher than the one under a mass-based cap, while provincial GDP losses have close relations with coal phaseout and permit scarcity. • A multi-regional recursive dynamic computable general equilibrium model with disaggregate power sector in China is developed. • Analyse China's unconventional design of a nationwide rate-based emissions trading with benchmark allocations. • The power-sector-only coverage would bring an opposite trend of electrification. • The key driving factors of provincial consumption losses are coal power phaseout and permit scarcity.