Abstract: This paper studied the effects of soil solar-disinfection by calcium cyanamide on the soil pH, temperature, and ammonium nitrogen content in vegetable field and the prevention effect of soil solar-disinfection by calcium cyanamide on the soilborne diseases of vegetable crops. During the process of the soil solardisinfection, the decomposed products of calcium cyanamide increased the soil pH value by 1.5-2.0 units and the soil ammonia nitrogen content by 2.0 mg·kg^-1, and raised the soil temperature via heat generation by 1-3 ℃. The appropriate duration of this disinfection was 20-25 d. Field experiment results showed that calcium cyanamide could effectively inhibit the cucumber fusarium wilt in 0-20 cm soil layer, with the control effect being increased with increasing disinfection duration. The fatality rate of the cucumber fusarium wilt was 23.6%-31.1% when the disinfection duration was 5 d, and reached 76.5%-84.7% when the disinfection duration was 15 d. The 800-1200 kg·hm^-2 field application rate of calcium cyanamide had the best control effect on vegetable root knot nematode, and made the vegetable root knot index decreased by 60%-90%.