The invention discloses a non-quenched-tempered high-strength steel plate resistant to large heat input welding and a manufacturing method thereof, and belongs to the field of low-alloy steel. According to the technical scheme adopted by the invention, the non-quenched-tempered high-strength steel plate resistant to large heat input welding is prepared from the following chemical components: Fe, C, Si, Mn, Ni, Nb, V, Ti, Ca, N, O and inevitable impurities, wherein in percentage by mass of the elements, 11.9-5.3C-0.91Mn-0.54Ni+0.46Si-0.73Nb+1.76V is greater than or equal to 9.92, and is smallerthan or equal to 10.68, and C / Nb+Ti / N is greater than or equal to 5.4, and is smaller than or equal to 6.9. The non-quenched-tempered high-strength steel plate has the beneficial effects that: the steel plate components are scientific and are reasonable in proportion, the process is easily controlled, performances of the produced steel plate are stable, comprehensive mechanical properties are excellent, low-temperature toughness of a welding heat affected zone during large heat input is excellent, welding efficiency is improved in a multiplying mode, energy consumption is relatively low, economical efficiency is good, the cost is low, industrial production is adapted, and the applied range is wide.