This study investigates the regulatory effects of different organic material inputs on soil physicochemical properties, as well as maize growth and development, in coastal saline-alkali land. The objective is to provide a theoretical basis for summer maize production in such environments. The experiment was conducted during the summer maize growing seasons of 2021-2022 in coastal saline-alkali farmland located in Wudi county, Binzhou city, Shandong province. The organic materials used included humic acid (3000 kg hm-2, HA), biochar (15,000 kg hm-2, BC), and bio-organic fertilizer (15,000 kg hm-2, BO), while the control (CK) had no organic materials added. The study examined changes in soil bulk density, total porosity, field capacity, pH value, electrical conductivity, and total organic carbon content in the 0-40 cm soil layer. Additionally, the effects of different organic material inputs on aboveground dry matter accumulation and maize yield formation were assessed. The results demonstrated that the application of humic acid, biochar, and bio-organic fertilizer can improve the physicochemical properties of saline-alkali soil. All three organic material treatments significantly reduced the bulk density of the surface soil, increased total porosity and field capacity, and reduced the pH value of the 0-10 cm soil layer by 0.17, 0.08, and 0.20, respectively. After two years of continuous application, humic acid significantly decreased soil electrical conductivity in the 0-40 cm soil layer by an average of 32.74%. Furthermore, all three organic materials significantly increased the total organic carbon content in the 0-20 cm soil layer, with the biochar treatment exhibiting a significant increase of 57.99%. Both humic acid and bio-organic fertilizer treatments significantly increased aboveground biomass and yield of summer maize. After two consecutive years of application, the humic acid treatment showed a significant yield increase of 11.01%, indicating superior performance. In conclusion, comprehensive analysis showed that the application of humic acid can improve soil physical structure, reduce the pH of the 0-10 cm soil layer, increase organic carbon content, decrease soil electrical conductivity, promote aboveground biomass accumulation in summer maize, and enhance grain yield under the conditions of this study. Moreover, humic acid application demonstrated increased net yield compared to the control after two consecutive years. Therefore, humic acid can be employed as an organic material to improve soil physical and chemical properties in coastal saline-alkali land, while promoting the growth and development of summer maize. Although bio-organic fertilizer also enhances soil physical and chemical properties, further localized experiments are necessary to verify its long-term economic effects.