Conventional dexterous hands have too many DOFs, their driver systems are too big to be installed in a humanoid robot arm, and their controls are too complex. This paper develops an under-actuated passive adaptive grasp humanoid robot hand named TH-1 Hand with control of grasping force. With the humanoid appearance and size, TH-1 Hand is light, fewer DOFs, and can be easily controlled. Its motors and driver circuit boards are embedded in itself. These features make it fit to be installed in a humanoid robot arm. In addition, for stably grasping operation, a mechanical finger with control of grasping force is designed and applied in TH-1 Hand’s index. To get more DOFs with fewer drivers, a novel under-actuated passive adaptive grasp mechanical finger is designed and applied in TH-1 Hand’s thumb.