Abstract: Pb2+ adsorption rate conditions of wheat bran residue optimized through quadratic orthogonal design.A quadratic regression orthogonal model was established to express the relationship between adsorption rate(Y)and five factors including pH (X1), temperature(X2), time(X3), concentration(X4), and addition amount(X5), as shown in the equation, Y=67.56718+9.52691X1+7.35677X2+0.09693X3-20.27575X4+8.44184X5-4.14591X12+0.36798X22-1.90632X32-1.36466X42-5.18757X52-2.83203X1X2+1.13932X1X3+1.79036X1X4-0.68359X1X5-1.20443X2X3+2.18099X2X4+0.61849X2X5+1.72526X3X4-1.79036X3X5+4.32943X4X5.The factor order on Pb2+ adsorption rate from strong to weak was concentration, pH, addition amount, temperature and time. According to this model, adsorption at 0.8g addition amount in 20mg/l for 1h using pH=8 and 100℃ of wheat bran residue revealed the highest adsorption, which was 99.99%. The experiment result was consistent with the theoreticl result of 98.91%. Wheat bran residue on Pb2+ adsorption with single molecule layer absorption dominant, and adsorption isotherm is fit to Freundlich adsorption isotherm. The adsorption rate for wheat bran residue to Pb2+ is quickly first, and then become slowly after more than 60min. Second kinetic model can describe the adsorption kinetics of wheat bran residue more better. In the low concentration of Pb2+ solution, the adsorption of wheat bran residue is better than activated carbon.