Abstract: In order to solve the central quality problems in the continuous casting production process of C610L slab，a two-dimensional solidification and transient heat transfermathematical model of 200mm×1500mm continuous casting slabfor simulated solidification heat transfer process was established.The solidification temperature field was reasonable displayed by calculated results andthe end point of solidification was 17.54m from the meniscus of the mould. Accuracy of the modelwas verified through the nail-shooting experimentsand the calculation results could guide the formulation of soft reduction.4millimeter reductions was applied in the final stage of solidification where central solid fraction ranged from 0.3 to 0.7 corresponding sector 6~7. According to macroscopic examination results，remarkable resultswasachieved from reduction programin improving center quality，and pushed the online defect rate from 3.34% down to 0.89%.

Key words: continuous casting slab, numerical simulation, soft reduction, center porosity