The invention belongs to the field of a transgenic technology, in particular to application of an OsPSK3 gene of rice on the aspect of improving the economical characters of the rice. When the gene is overexpressed in indica type rice, a transplant plant exhibits a stronger growth tendency as follows: the germination and the growth of plants are quicker; a fibrous root system is more advanced than the contrast; the color of the leaves is obviously darkened and the stem is prolonged; and the stem is thicker and the color of the leaves is green black when the plants are ripe. A series of changes in economical phenotypes strengthen the growth tendency of the plants; and the phenotype with the content of the chlorophyll in the leaves obviously increased from the seedling stage strengthens thephotosynthesis of the species. The invention has the advantages that the OsPSK3 transgenic rice is cultivated by utilizing a gene engineering method; and the economical characters of the growth tendency, the photosynthesis and the like of the rice crop are enhanced.