The invention aims to provide an adjustable single-finger constant speed passive movement device and a single-finger muscular tension detection method. The device is characterized in that a bionics principle is based to simulate finger constant speed stretching, i.e., stretching movement; through a guide line, an external force is applied to an internal collected finger, the finger passively and slowly stretches at a constant speed under the action of the external force, the external expressive force of tension and muscular tension on the guide line can be equal in the aspect of amplitude, anda tension and pressure sensor connected to one end of the guide line is used for detecting the tension of the guide line so as to indirectly obtain the maximum muscular tension of the finger. In addition, the device is a muscular tension detection device which aims at a single finger, and is suitable for detecting the muscular tension of the thumb and the other four fingers. The device comprisesa rack component, a finger external bone fixing component, a position regulation component and a detection and control component, wherein the guide line starts from the detection and control component, passes through the position regulation component and stops at the finger external bone fixing component; the position regulation component is fixed on the rack component; the detection and control component is fixed on the position regulation component. According to the device, the muscular tension in a finger constant speed passive stretching process is detected, the maximum muscular tension ofthe finger of a patient can be measured, and therefore, a basis is provided for the rehabilitation of the hand of the patient who suffers from chirismus and the like.