On the purpose of integrated optimization of production scheduling and preventive maintenance for multi-product tasks which in producing workshops, an integrated optimization model of production scheduling and preventive maintenance was established comprehensively, in which processing sequence, batch quantity, preventive maintenance measures and other factors were taken into account consequently, on the premise that there are sufficient orders, as well as the joint optimization objective to minimize overall manufacturing costs and processing time. In view of the characteristics of the model, based on the non-dominated sorting genetic algorithm, a single-parent genetic algorithm with variable-length genome was put forward as the resolving method for the model based on the catastrophe mechanism and glory space, which keeps in combination with introducing interruption and splice operators. Besides, under different parameter conditions and various scales of problems, simulative experiments were conducted to verify the efficiency of the proposed algorithm to resolve complex integrated optimization problems of production scheduling and preventive maintenance.