The present disclosure provides a siRNA for inhibiting the expression of apolipoprotein C3 (ApoC3) gene, and a pharmaceutical composition and a conjugate comprising the siRNA； wherein each nucleotide in the siRNA is independently a modified nucleotide, and the siRNA comprises a sense strand and an antisense strand； the sense strand comprises a nucleotide sequence A, the nucleotide sequence A having the same length as the nucleotide sequence as represented by SEQ ID NO:1 with no more than 3 nucleotide differences； the antisense strand comprises a nucleotide sequence B, the nucleotide sequence B having the same length as the nucleotide sequence as represented by SEQ ID NO:2 with no more than 3 nucleotide differences.
