Abstract: Backlash-adjustable worm drive is classified by adjusting theory. The adjusting relationships for each kind of backlash-adjustable worm drive are discussed, and the advantages and disadvantages are reviewed. Based on the development of worm drive and the characteristics of industrial development in recent years, the development trend and the research hotspots of backlash-adjust worm drive are predicted. The study can offer guidance for us to select backlash-adjustable worm drive from existing ones and research novel backlash-adjustable worm drive.