Countries are committed to addressing climate change and implementing carbon emission trading plans to reduce greenhouse gas emissions, internalizing carbon emissions as part of corporate operating costs, and the carbon emission prices formed by transactions guide companies to choose the most cost-effective means of carbon reduction. The main problems of the current carbon trading system are fragmented implementation, lack of transparency leading to excessive credit and double-spending attacks, and large transaction costs caused by exchanges through agents. In this paper, by utilizing blockchain technology, based on the transparency, security, and immutability that this mechanism can provide, it brings higher transparency, accessibility, liquidity, and standardization to the carbon market. At the same time, in order to improve the storage and query efficiency of the carbon allowance trading system, this paper proposes a cross-chain carbon trading model that stores different types of information on different blockchains to improve the scalability of the blockchain. In order to solve the problem of cross-chain calls to unreliable information faced by cross-chain technology, this paper proposes a cross-chain trusted payment verification mechanism based on Merck proof to ensure the authenticity, real-time, and security of cross-chain information, making inter-chain information interaction in carbon allowance trading more convenient and accurate.