A conceptual dispersion imaging spectrometer (DIS) is proposed. It consists of a telescope, four prisms, an imaging lens, and a detector. The first prism allows only the first set of wavelengths along the first direction to pass and disperse. The second prism allows only the second set of wavelengths along the second direction, which is perpendicular to the first. The third and fourth prisms are used to compensate for the angular deviations from the optical axes of the first and second prisms, respectively. The proposed DIS disperses the spectra of a target to form an L-shaped dispersion pattern (LDP). The theoretical calculation and numerical simulation of the LDP are presented. The DIS can locate multiple targets based only on data obtained from a single frame. It is suitable for detecting and locating energetic targets in real time.