The invention discloses a tomato stress-resistant gene, a protein coded by the tomato stress-resistant gene and application of the tomato stress-resistant gene, the phenotype of drought resistance of the tomato stress-resistant gene is most obvious in low-temperature stress treatment, salt stress treatment and drought stress treatment, the salt resistance of the tomato stress-resistant gene is second, and the low-temperature resistance of the tomato stress-resistant gene is relatively obvious. The low temperature resistance, the salt resistance and the drought resistance of the overexpressed SlCIPK8 transgenic plant can be improved by improving the activity of antioxidant enzyme, so that the method has important significance on genetic improvement and resistant variety breeding of tomatoes, and has very high application value.