Abstract: The finite difference model for 320 mm×410 mm continuously cast bloom of 1.4418 martensite stainless steel was established based on the equipment condition in a domestic factory,and it was verified by the shell thickness and surface temperature in the plant.The solidification characteristic and mechanical reduction reasonability in continuous casting of 1.4418 martensite stainless steel were discussed numerically,and the most suitable casting speed was found as 0.45m/min.Two sets of mechanical reduction parameters were designed with total reduction amount of 12 mm and 15 mm,respectively.The industrial test was carried out according to the optimized schemes by numerical modelling,and the successful operation was achieved within the rated power range of withdraw units.The best center quality of the bloom for 1.4418 martensite stainless steel was obtained when the casting speed was0.45m/min with the designed reduction amount for No.2—5 withdraw units about 4 mm,4 mm,4 mm and 3 mm respectively,and the pass rate for the level A flaw detection was measured to be around 97%,satisfying the requirement of batch production and delivery.