Aiming at the poor physicochemical properties, the low fertilizer use efficiency and the weak crop growth in saline soils, a saline soil was ameliorated with different biochar fertilizers in this study. Brassica chinensis and cotton were used as research materials in this pot experiment. Five different treatments were conducted, i.e., non-fertilized control group (CK0), conventional fertilization (CK), conventional fertilization+biochar (C1), conventional fertilization + biochar + nitrification inhibitor (C2), conventional fertilization + biochar + Calcium sulphate (C3). The growth and photosynthesis of Brassica chinensis and cotton were measured. The results showed that C3 treatment was more effective in crop growth than that of CK. The plant height and weight of Brassica chinensis were increased by 32.7% and 112.0%, respectively, and the chlorophyll content and net photosynthetic rate were increased by 45.5% and 32.9%, respectively. The intercellular CO₂ concentration and transpiration rate were decreased by 15.0% and 59.2%, respectively. Spectral analysis indicated that the C3 treatment had higher reflectance and better leaf tissue. The experimental results also indicated that, compared to CK, biochar treatments promoted cotton growth, expressed as increase in chlorophyll content significantly, decreasing malon dialdehyde content and catalase activity in leaves, leading to the enhanced stress resistance and the reduced plant damage. At the same time, the intercellular CO₂ concentration in cotton leaves was reduced, and the water use efficiency was improved. Soil analysis suggested that the application of biochar significantly improved the physical and chemical properties of soil. Compared with CK, the organic matter content, available phosphorus content and alkali nitrogen content in C2 treated soil were increased by 57.3%, 22.9% and 40.8%, respectively. However, the influence on soil available potassium content and pH value was not obviously, and C3 treatment had an obvious increase in soil electrical conductivity. Therefore, when ameliorating the saline soil, it is necessary to pay attention to the reasonable application amount of the modifiers to prevent further accumulation of soil salinity.