The comprehensive weights of indicators in the accurate design assessment indicator system for new generation mass-production slab steel plants are determined by combining of 71 expert opinions using Weighted Arithmetic Mean Method (WAMM). The obtained comprehensive weights indicate that, among the four composite indicators, the weight of economics/investment level is the highest, and weights of process operation high-efficiency level and ecologization level are relatively lower. Among indicators of economics/investment category, the weight of rate of return on investment is much higher than other indicators. Among indicators of procedure operation category, in general, the weights of blast furnace and basic oxygen furnace are the highest. Among indicators of process operation category, the weight of inter-procedure parameter is slightly higher than that of process running time. Among indicators of ecologization category, the source technology has a much higher weight than intermediate and end technology