The real production scheduling problem between steel-making and continuous-casting can be modeled as Flow Shop Scheduling Problem. Waiting time must be considered for the reason of the temperature decrease of molten steel. The genetic algorithm with an initial population generation mechanism and a piecewise fitness function is proposed for solving the problem. The test results show that the proposed algorithm can find better solutions. A real case of steel-making and continuous-casting scheduling problem is computed and it shows the algorithm is effective.