The invention discloses a thin seam gob-side entry retaining laneway side filling support method, a metal mesh box body is arranged in the design position which is temporarily supported on a filling wall body, a notch is reversed in one surface, facing the gob-side entry retaining laneway, of the metal mesh box body, and a bleeding woven bag is arranged on the inner wall of the metal mesh box body; gangue which is excavated from a bottom excavation section is directly thrown into the metal mesh box body through the notch, and after the metal mesh box body is filled to the top, grouting is performed for gangue seam filling; the notch is complemented by a metal mesh piece and the woven bag, and grouting to the notch is continued so that the filling wall body becomes complete; after bleeding solidification, the filling wall body is formed; the above steps are cycled continuously, and the section of the single prop with support force after solidification is removed at the right time and moved to next step for recycling until the working face is finished. According to the thin seam gob-side entry retaining laneway side filling support method, the construction technology and the filling technology are simple, the labour intensity is low, the operation is easy, coal pillar loss in the mining working face zone can be improved, and the tension of the relation of excavation and recovering is effectively relieved.