The invention provides three-filament twisting parallel spun yarn, a spinning device and a spinning method. The yarn comprises an inner core yarn layer and an outer twisting layer, wherein the inner core yarn layer comprises weakly twisted staple fiber yarn or combination of staple fiber yarn and core yarn; the outer twisting layer comprises three strands of twisting yarn and two strands of twisting yarn; the inner core yarn layer is subjected to twisting processing by the outer twisting layer to finally obtain the needed yarn. When in spinning, three yarn cylinders arranged up and down are additionally mounted on a hollow spindle, and the yarn cylinders and the hollow spindle are connected through controllable gears, so that the controllable feeding of the three strands of twisting yarn can be realized. Through the adoption of the method, the controllable twisting of the three strands of yarn of the inner core yarn layer can be realized, so that the resultant yarn quality can be improved, the appearance style of the yarn can be enriched, and the added value of the product can be improved.