In order to study the application effect and safety of the titanium gypsum with harmless treatment as a soil conditioner, we employed a systematic test of ingredients identification, soil column leaching, and potted experiment to study the content of harmful elements in titanium gypsum and titanium gypsum leaching solution, and to study the effect of gypsum on the growth, yield and leaf photosynthetic rate of rape seedlings simultaneously. Results showed that the main elements in leachate were calcium sulfate and iron oxide, all content of heavy metals in titanium gypsum were below the national safety standards, the presence of elements in the leachate did not contaminate the soil and groundwater after application. With the increase proportion of titanium gypsum, rape seedlings production increased firstly and then decreased, excessive titanium gypsum could inhibit the growth of rape seedlings. Titanium gypsum showed the best effect at the ratio of 1:4 to the soil. The leaf transpiration rate increased by 11.86% after 20 days of seedling emergence as compared to that of conventional soil cultivation. Thirty days after seedling emergence, the plant photosynthesis, plant height, and biomass increased by 4.33%, 12.97%, and 14.08% than those of the conventional soil cultivation, respectively. Correlation analysis showed that the relationship between yield (y) of rape seedlings and the addition ratio (x) of titanium gypsum was y=0.0001x³-0.0212x²+0.6966x+41.815 (R2=0.999 4). In actual production, the application of 300 tons of titanium gypsum per hectare should be the best application dose to improve the crop productivity.