The invention discloses a goaf subsidence region sinkage monitoring system and method, belonging to the field of environment treatment of mining areas. The method comprises the following steps: making a monitoring hole from the ground to the goaf floor, arranging a steel base retaining cylinder on the bottom of the hole, and anchoring to wall rock through an annular bulge under the action of structural adhesive or cement mortar; respectively and mutually nesting a constant-speed sinkage layer retaining cylinder, a low-speed sinkage layer retaining cylinder and a slight-speed sinkage layer retaining cylinder with the steel base retaining cylinder layer by layer through a seal ring and balls, and anchoring with the affiliated layer through the annular bulge; and by using a first fixed end, a first measuring tape, a second fixed end, a second measuring tape, a third fixed end and a third measuring tape, reading the sinkage values of the layers by the aid of a ground pulley and a counterweight-weight composite structure, thereby implementing the monitoring on the goaf subsidence region. The system and method can implement real-time continuous small-scale monitor on sinkage development of the goaf subsidence region, and provides powerful support for environment treatment of mining areas.