The invention relates to a low yield ratio chromium-molybdenum steel plate and a production method thereof, belonging to the technical field of steel smelting. The production method comprises the following processes of smelting continuous casting, heating and rolling, and thermal treating. The steel plate comprises the following components by weight percent: more than or equal to 0.13% and less than or equal to 0.17% of C, more than or equal to 0.30% and less than or equal to 0.40% of Si, more than or equal to 0.50% and less than or equal to 0.70% of Mn, less than or equal to 0.007% of P, less than or equal to 0.005% of S, more than or equal to 1.00% and less than or equal to 1.10% of Cr, more than or equal to 0.50% and less than or equal to 0.65% of Mo, less than or equal to 0.20% of Cu, more than or equal to 0.10% and less than or equal to 0.20% of Ni, less than or equal to 0.003% of Sb, less than or equal to 0.010% of Sn, less than or equal to 0.010% of As, the balance of Fe and inevitable impurities. The low yield ratio chromium-molybdenum steel plate meets the requirement of domestic and aboard petrifaction and coalification industries on lowing the yield ratio of the chromium-molybdenum steel plate used at high temperature environment, can be widely used on devices such as delay coking devices of coke drums and hydrogenation reactor and the like, has good cold bending property, does not crack when being manufactured, and has good rebound elasticity and good plate shape.