Field experiments were used to determine the main nutrient content of the soil at 25, 50, and 75 days after the tobacco seedlings were transplanted. And the effects of three soil amendments: calcium cyanamide, biochar and microbial fertilizer + cake fertilizer on enzyme activities and nutrients in tobacco planting soil were studied. The results showed that the soil available potassium treated with biochar and microbial fertilizer + cake fertilizer increased by 31.80% and 12.52%, respectively, compared with the control, and the soil available phosphorus and alkali-hydrolyzable nitrogen content of the calcium cyanamide treatment decreased by 7.30% and 2.01%, respectively. At 75 days after transplanting, soil catalase activity and urease activity in amendment treatments were increased by 11.79%-15.38% and 19.10%-25.14% compared with the control, respectively; and catalase activity and urease activity in calcium cyanamide treatment was the highest while in charcoal treatment was the lowest; soil neutral phosphatase was increased by 6.96%-14.96% compared with the control, which in microbial fertilizer + cake fertilizer treatment was the highest, and in calcium cyanamide treatment was the lowest. From the overall effect, the application of biochar modifier has the best effect.