The present invention provides a protein OsXCL relating to grain shape and leaf shape of rice, its derived proteins and their coding genes. Transgenic rices over-expressing OsXCL gene present phenotypes as increase of grain length, grain weight and number of grains per panicle, and leaf rolling and so on. The present invention also provides the method for obtaining transgenic plants by transforming the coding genes of OsXCL or its derived proteins into objective plants.