The invention discloses a high-quality non-quenched and tempered seamless steel tube for drilling and a manufacturing method thereof. The tube for drilling comprises, 0.36% to 0.38% of C, 0.25% to 0.35% of Si, 1.46% to 1.66% of Mn, 0.26% to 0.32% of Mo, 0.06% to 0.08% of V, 0.022% to 0.032% of Ti, 0.014% to 0.018% of Alt, 0 to 0.010% of P, 0 to 0.010% of S, 55 ppm to 75 ppm of N, 0 to 1.5 ppm of H, 0 to 25 ppm of O, 0 to 0.038% of As+Sn+Pb+Sb+Bi, the balance Fe and inevitable impurities. The metallographic structure is the uniform and fine granular bainite structure; according to the performance, the tensile strength Rm is larger than or equal to 1100 MPa, the yield strength Rp0.2 is larger than or equal to 960 MPa, the elongation percentage A is larger than or equal to 16%, and the longitudinal impact energy AKU2 is larger than or equal to 75J. The granular bainite structure formed by the unique ingredients of the non-quenched and tempered steel meets the design requirement for the tensile strength, the yield strength, the elongation percentage and the longitudinal impact energy, the same quality requirement is met compared with the quenching and tempering technology adopting quenching and high temperature tempering, one heating step is omitted, the production process is shortened, and the production efficiency is improved.