Adapter signatures, as an extended form of digital signatures, achieve the binding of signatures to secret values and are widely used in blockchain payment channels, cross-chain atomic swaps, and supply chain finance. However, the single-key control mode adopted by adapter signatures exposes them to the risk of key leakage. If the key is lost, leaked, or damaged, all resources dependent on it will become uncontrollable. The SM9 digital signature is an identity-based cryptographic algorithm independently developed in China and became a national cryptographic standard in 2020. It is widely used in key industries such as government affairs, finance, and energy. However, the SM9 digital signature exhibits certain limitations in complex collaborative cross-chain atomic swaps in distributed scenarios. To expand the adaptability of the SM9 algorithm in distributed scenarios, this study proposes an SM9 threshold adapter signature scheme. By distributing the key among multiple participants for joint management, the single-point failure problem of the SM9 adapter signature is addressed. To reduce the communication rounds and computational overhead of multiple participants, a method combining secret sharing and secure multi-party computation is adopted to transform complex operations in the algorithm into efficient local linear operations, thus enabling collaborative multi-party computation without exposing any secret shares. In addition, the proposed scheme can be further applied to scenarios such as fair exchange. Compared with existing schemes, the proposed scheme reduces computational overhead by 60.17% and communication complexity from O(n²) to O(n).