A device for detecting a two-dimensional morphology of a wafer substrate in real time. The device comprises: a first calculation module, a second calculation module and an analysis module, wherein the first calculation module calculates the curvature CX between any two points of incidence on the wafer substrate in an X direction of a substrate to be detected according to position signals of N light spots; the second calculation module calculates the curvature CY at any one point of incidence on the wafer substrate in a moving direction, i.e. a Y direction, of the substrate to be detected according to the position signals of N light spots. The device can be adapted to a sapphire substrate on a graphite disc which rotates at a high speed.