The invention relates to a sewing machine for up-down differential feeding. The sewing machine comprises a secondary feeding adjusting mechanism, a feeding shaft and a feed lifting rock shaft, wherein the secondary feeding adjusting mechanism comprises a lower differential feeding adjusting crank and a first tooth frame seat which are fixed on the feeding shaft, a lower differential feeding crank which movably sleeves the feeding shaft and a lower differential transmission crank which movably sleeves the feed lifting rock shaft; the first tooth frame seat is connected with a feeding tooth; the lower differential feeding crank is connected with a lower differential feeding tooth; the lower differential feeding adjusting crank, a first lower differential feeding connecting rod, the lower differential transmission crank, a second lower differential feeding connecting rod and the lower differential feeding crank are hinged and linked in sequence; the hinging position between the lower differential feeding adjusting crank and the first lower differential feeding connecting rod is adjustable. The hinging position is adjusted so that a force arm relation between the lower differential feeding adjusting crank and the first lower differential feeding connecting rod is changed and a relation of swinging and transferring the feeding shaft to the feeding tooth and the lower differential feeding tooth is changed, namely the lower differential feeding adjustment is realized.