As a beneficial element, Si plays a significant role on crop growth promotion and resistance strengthen. In the present study, a two-year field experiment was carried out in 2013 and 2014. The influence of water-cooling slag and steel slag on the growth and yield of maize were studied, and the effects of Si application on maize Si and P uptake as well as Si fertilizer utilization efficiency were analyzed. It was found that both Si fertilizers of water-cooling slag and steel slag significantly increased soil available Si content (P<0.05). For instance, compared to the CK, the treatment of water-cooling slag application increased soil available Si by 36.9%, 15.3% and 9.7% in tasseling, dough and mature stage, respectively. The two kinds of Si fertilizer treatments significantly improved the leaf area index and dry matter accumulation of maize (P<0.05). Also, maize yields of 17 979 kg/hm² in water-cooling slag treatment and 17 134 kg/hm² in steel slag treatment were gained, 18.9% and 13.3% higher than the CK, respectively. Compared with the CK, Si fertilizer application increased Si and P uptake by maize plant significantly (P<0.05), by 14.6% for Si uptake and 11.5% for P uptake in water-cooling slag treatment and by 10.4% for Si uptake and 8.7% for P uptake in steel slag treatment, respectively. A significant positive correlation was observed between maize Si uptake and P nutrition (P<0.01) furthermore, Si fertilizer application increased obviously plant P nutrition and P partial productivity. Si fertilizer utilization efficiency was 38.9% in water-cooling slag treatment and 27.8% in steel slag treatment, indicating water-cooling slag fertilizer is better than steel slag.