The invention discloses application of a tomato SlSPY gene in controlling the ripening process of tomato fruits. The expression level of the tomato SlSPY gene is increased through a gene overexpression technology; the nucleotide sequence of the tomato SlSPY gene is a nucleotide sequence shown in SEQ ID NO: 1. A tomato SlSPY overexpression plant and a gene knockout plant are constructed through a gene means, the expression level of the gene SlSPY is regulated and controlled to research the regulation and control mechanism of the tomato SlSPY gene on ripening of the tomato fruits, and the resultshows that SlSPY overexpression can improve the sensitivity of the tomato fruits in a green ripe stage to ethylene, accelerate color changing of the tomato fruits and promote fruit softening and accumulation of carotenoid such as lycopene. In the SPY gene knockout plant, the color changing and softening process of the tomato fruits is inhibited, and accumulation of the carotenoid such as the lycopene is less than that of wild type fruits in the same period.