Abstract: To achieve the "dual carbon" goal and promote the development of low-carbon industries, the government has adopted a series of carbon emission reduction policies, including carbon tax and carbon trading, to encourage enterprises to transition to low-carbon development. As an effective approach to reduce carbon emissions, remanufacturing has been widely adopted by enterprises. Especially in the context of the digital economy, blockchain technology provides a novel means of information sharing in remanufacturing processes. By considering carbon tax policies, this paper establishes game models under three remanufacturing modes: in-house remanufacturing, authorized remanufacturing and outsourced remanufacturing, based on whether enterprises invest in blockchain technology. Subsequently, the adoption strategy of blockchain technology and its impact on remanufacturing mode choices are analyzed. Results reveal that: 1) carbon tax policies increase the retail prices of both new and remanufactured products while reducing the market demand for new products and increasing the demand for remanufactured products. When the unit blockchain investment cost is below a certain threshold, the adoption of blockchain technology further shifts the demand from new products to remanufactured products, achieving a Pareto improvement in the profits of both manufacturers. 2) Original equipment manufacturers always prefer the in-house remanufacturing mode regardless of whether blockchain technology is adopted. For remanufacturers, the outsourced remanufacturing mode is preferred when consumer preference is high and the recycling scale coefficient of used products reaches a certain threshold. 3) In-house remanufacturing is always effective in reducing environmental impact and increasing consumer surplus, regardless of whether the supply chain adopts blockchain technology. Moreover, the outsourced remanufacturing mode is more effective in optimizing both utilities than the authorized remanufacturing mode when consumer preference is high.