Protein for controlling rice grain weight as well as coding gene and application thereof

The invention discloses protein for controlling the rice grain weight as well as a coding gene and an application thereof. The protein is those shown as 1) or 2): 1) protein formed by SEQ ID NO. 2 amino acid residue sequences in a sequence table; and 2) protein which is formed by substituting and/or deleting and/or adding SEQ ID NO. 2 amino acid residue sequences in the sequence table through one or a plurality of amino acid residues and has the same activity as the SEQ ID NO. 2 amino acid residue sequence. The gene can be used for cultivating rice new varieties increased in thousand-grain weight, so that the significance is important.