The invention relates to a compact radar mast provided with a semi-round illuminating light, comprising a man light mast, wherein two sides of the main light mast are provided with a radar supporting structure respectively, and the main light mast and the radar supporting structures are positioned on a same straight line; and the main light mast is divided into a signal light mast at the upper, a base structure at the middle and a supporting column structure at the lower. The compact radar mast is characterized in that the signal light mast comprises four vertical rod bodies, wherein the cross sections of the four vertical rod bodies form a rectangle, a plurality of pairs of branch rods horizontally extending outwards towards the transverse direction are arranged on each rod body, and each branch rod can be correspondingly provided with a plurality of pairs of semi-round illuminating lights; and the central line of a blind area of each semi-round illuminating light is parallel to the connection line of the main light mast, the radar supporting structures and the deck connection point, and the area at which the radar supporting structures are positioned is totally covered. The compact radar mast solves the problem of layout of signal lights which are gradually increased, and the structural utilization rate of the radar mast is utilized; the volume, the outreach and the weight of the radar mast are reduced while the stability is good; the blind area of the all-round lights is reduced to be beneficial for safe navigation of ships; and the interference between inner structures of the radar mast is reduced.