Abstract: The effective utilization of industrial surplus is an important issue in many industries for reducing the amount of cement or lime by a large margin. However, the application and the methods determining dosage ratio of such materials usually rely on a large number of experiments and experience, lacking guiding principles for reasonably proportioning methods. This study aims at proposing an approach for designing dosage ratio of multi-source curing agents, taking common industrial solid wastes of steel slag, fly ash, phosphogypsum and lime as an example. The unconfined compressive strength tests were performed on the stabilized samples for identifying the influence of three chemical moduli on strength behavior. The scanning electron microscopy tests and the neural network method were also carried out for understanding the changing law in micro-behavior with different three chemical moduli. The research results show that the solidified samples within the range of three chemical moduli has a higher strength than those out of the scope. It is also found that the calcium sulfur ratio has a significant impact on the strength of the solidified samples. Consequently, the optimization method is proposed for determining the proportions of the multi-source curing agents based on the three chemical moduli combining with the calcium sulfur ratio. The mechanism responsible for the influence of oxide and rod AFt gel microstructure on the strength of the solidified samples is revealed by linking the macro- and micro- behaviour. The changing patterns of microstructure induced by the change in three chemical moduli and the calcium sulfur ratio are understood. The correlations between the strength behavior and the overall area, number and size of pores are established.