To study the spatial spectrum characteristics of scattered light from a laser illuminated bubble curtain in the wake, the Monte Carlo model based on the single-bubble Mie scattering theory was used. The propagation process of each photon in the wake bubble group underwater was tracked, and the coordinates of the photon position reaching the receiving plane were recorded. The effects of propagation distance, bubble size, and bubble number density on the full-width at half-maximum (FWHM) of spatial spectrum of forward scattered light from wake bubbles were investigated. The results show that with the increase of the transmission distance, the bubble size and bubble number density increase, and the FWHM of the spatial spectrum decreases. This feature of spatial spectrum can be used as one of the criteria for ship wake identification.