Protein extraction from Gualou seeds were studied, and Kjeldahl method and Sodium dodecyl sulfonate-polyacrylamide gelelectrophoresis (SDS-PAGE) were used to characterize the properties of extracted proteins. The optimum extraction parameters were as follows: the extraction solution was 0.2 mol/L phosphate buffer (pH, 8.0) with 5% NaCl, and the ratio of solid to liquid was 1:10. A protein yield of 75.01% was obtained under the optimal extraction conditions. The SDS-PAGE analysis showed that the proteins extracted from Gualou seeds have apparent molecular weights varying from 10 to 30 kDa, mainly close to 30 kDa.