The invention discloses a large-thickness 14Cr1MoR steel plate and a production method thereof. The large-thickness 14Cr1MoR steel plate comprises the following chemical components in percentage by mass: 0.12-0.14% of C, 0.5-0.6% of Si, 0.40-0.50% of Mn, 0.006-0.007% of P, equal to or less than 0.005% of S, 1.3-1.5% of Cr, 0.58-0.60% of Mo, 0.10-0.20% of Ni, equal to or less than 0.05% of Nb, equal to or less than 0.20% of Cu, equal to or less than 0.003% of Sb, equal to or less than 0.010% of Sn, equal to or less than 0.010% of As and the balance of Fe and unavoidable impurities. The production method comprises the procedures of smelting, continuous casting, heating, rolling and thermal treatment. According to the production method, the two-stage rolling control technology and the thermaltreatment technology of normalizing and tempering are adopted to solve the problems that the crystal particles are thick, non-uniform, lower in impact toughness and higher in hardness, and the head performance and the tail performance of the steel plate differ widely.