In present study, Gualou seed proteins were extracted from its by-products, and the molecular properties of the proteins were also observed. The results showed that the Gualou seed proteins mainly consisted of salt-soluble protein (55.3% of extracting yield) and alkali-soluble protein (15.8% of extracting yield), and the alkali-soluble protein may be linked with pigments because the protein solution appeared to be dark brown. Sodium dodecyl sulfonate-polyacrylamide gelelectrophoresis analysis was used to test the subunit molecular weight distribution and the result revealed that subunits of salt-soluble and alkali-soluble proteins mainly distributed from 10 to 32 kDa. The molecular weight distribution of the samples, observed by size exclusion chromatography showed that there were more fractions with large molecules larger than 10⁶ Da in alkali-soluble protein. Microstructural observation by scanning electron microscopy displayed that the salt-soluble proteins were globular proteins with size of 2～5 μm, while alkali-soluble protein were aggregates with compact structure.