The work presents density (

ρ

) and viscosity (

η

) data of binary system polyethylene glycol 600 (PEG) + dimethyl sulfoxide (DMSO) over the entire concentration range at

T

=(298.15

303.15

308.15

313.15 and 318.15) K and atmospheric pressure. On the basis of density and viscosity values

the excess properties of PEG (1) + DMSO (2) mixtures

including excess molar volume (

V

m

E

)

viscosity deviation (△

η

)

excess free energies of activation (△

G

*E

)

and isobaric thermal expansion coefficient (

α

p

)

were calculated. At the same time

in order to conjecture the density viscosity under different conditions

the density and viscosity data were fitted with the corresponding formula. The calculated results of

V

m

E

△

η

and △

G

*E

were fitted with the Redlich-Kister equation to derive coefficients and estimate the standard deviations (

σ

) between the experimental and calculated values. Moreover

the intermolecular interaction of PEG with DMSO was discussed on the basis of FTIR and UV-Vis sp

ectral results of PEG (1) + DMSO (2) mixtures. The results indicated that there were the hydrogen bonding and interactions of hydroxyl hydrogen atoms in PEG with oxygen atoms in DMSO.