A miniature Fourier-transformed spectrometer based on the subwavelength slit-groove configuration with the interference of surface plasmon wave is proposed. By gradually increasing the set distance of the slit and groove, the interference fringes with different optical path difference is obtained. By then adding the Fourier-transform process, the spectrum of the incident light is recovered. By analyzing the interference in the slit-groove structure, the theory of the spectrometer is obtained. With the finite difference time domain (FDTD) method, the structure parameters are optimized firstly and then the spectrometer in spectrum recovery is demonstrated and the resolution of 3.84nm is achieved at the wavelength of 750nm.