The present invention relates to a method for manufacturing a paper straw, the method comprising: a paper roll transmission step, a paper strip heating step, a bonding and shaping step and a cutting step. Wherein, a plurality of raw paper rolls face a connection position jointly to transmit a raw paper strip, the raw paper strip includes a paper material and a dry hot-melt adhesive. The dry hot-melt adhesive of the raw paper rolls is heated for changing into flow hot-melt adhesive. Then the raw paper rolls is transmitted to the connection position for rolling jointly, and the flow hot-melt adhesives are bounded on another raw paper strip to form a pipe. Finally, the pipe is cut to form at least one paper straw after the pipe exceeds a setting length. The present invention uses dry adhesive to manufacture paper straw, without the excessive glue problem and mold phenomenon of the traditional wet bonding method as well as without an extra dry fixing step of traditional manufacture process, so the productivity will be raised significantly, and the defect rate will be reduced.