Abstract: The interaction between sunset yellow (SY) and bovine serum albumin (BSA) was studied by differential pulse voltammetry. The results showed that the decrease of peak current was caused by the formation of SY and BSA (approximately, 1:1) composite. The electrostatic force played the main role in their combination. The binding constant was decreased with increasing temperature. The research results are helpful in understanding the metabolism mechanism of SY and BSA at a molecular level, and provide some theoretical references for the study of the biological metabolism mechanism of SY.