Transaminases have important applications in the synthesis of drug intermediates such as chiral amines. However, natural transaminases exhibit suboptimal thermal stability, limiting their further applications. Building upon an Rhodobacter sp.-derived (R)-selective transaminase (RbTA), we report a dual-region coupling engineering approach to improve thermostability of RbTA by strengthening the core hydrogen-bond networks and rigidifying the flexible surface loop. Through single strategy, we identified 4 thermostability improved single mutations, among which I249Q demonstrated the most substantial improvement, achieving a 18-fold increase in half-life (t