Abstract: To investigate the influence and contribution of the oxidation of dimethylsulfide (DMS) released from the tropical western Indian Ocean to the formation of methanesulfonic acid (MSA) and sulfate (\mathrmSO_4^2- ) in marine aerosols, atmospheric DMS samples and aerosol particle samples were collected in the tropical western Indian Ocean from December 2021 to February 2022. The distribution characteristics of atmospheric DMS and MSA and \mathrmSO_4^2- (including non-sea-salt \mathrmSO_4^2- : nss-\mathrmSO_4^2- ) concentrations in aerosols were studied. The relationship between atmospheric DMS and aerosol MSA and \mathrmSO_4^2- was explored, and the quantification of DMS oxidation on atmospheric nss-\mathrmSO_4^2- generation was assessed. Results showed that the atmospheric DMS concentration over the tropical western Indian Ocean was (353.4±169.1) ng·m⁻³, comparable to the aerosol \mathrmSO_4^2- concentration (224.6±88.46 ng·m⁻³), but significantly higher than the MSA concentration (4.12 ng·m⁻³). The mass concentration ratios,c(MSA)/c(DMS) (R_m) and c(nss-\mathrmSO_4^2- )/c(DMS) (R_s), were (0.012±0.010) and (0.465±0.464), respectively. The difference indicated that the main product of DMS oxidation in the tropical waters of the Western Indian Ocean is nss-\mathrmSO_4^2- rather than MSA. Furthermore, the contribution of biogenic sulfur in the tropical western Indian Ocean to nss-\mathrmSO_4^2- in aerosols could reach 65%, indicating the significant impact of tropical western Indian Ocean marine biological processes on the regulation of atmospheric nss-\mathrmSO_4^2- above it.