To address the structural complexity, actuation redundancy, and insufficient compliance of fully actuated dexterous hands, an underactuated dexterous hand based on a rigid-flexible coupled structure is proposed. According to the motion characteristics of the human hand, three motors are employed to drive five fingers, achieving compliant coupled bending and multi-finger coordinated control. Each finger consists of a composite structure of a rigid skeleton and flexible joints, with cable used to imitate tendon traction, and torsion spring-pin structures introduced at the joints to emulate the elasticity of soft tissues, enabling passive adaptation to the target shape and compliant rebound during grasping. Tactile sensor arrays are integrated on the fingertips and palm, which, together with motor encoders, form a combined force-position perception system capable of real-time detection of contact state, grasping force and joint posture, thereby effectively enhancing environmental perception and grasp stability. The hand weighs only 482 g and demonstrates strong task adaptability, achieving 82.2% success in power grasps and 46.7% in precision grasps across 16 representative tasks, and it can serve as an end-effector to perform grasping, transportation, and stacking operations, enabling interaction in multiple scenarios. In multi-object tactile recognition experiments, the proposed sensing approach achieves an average accuracy of 96.5% for six target objects, validating its effectiveness in tactile perception. During constant-force grasping and disturbance compensation tests, force fluctuation remains within ±0.3 N and the system rapidly restores stability after sudden load changes, indicating robust and stable control performance. Overall, the proposed dexterous hand achieves simplified structure, compliant grasping, and multimodal sensing capabilities, making it suitable for human-robot interaction and mobile manipulation applications.