A novel chemiluminescence(CL) biosensor for the determination of oxalate is presented in this paper. It is based on the CL reaction between luminol, immobilized on an anion-exchange column, and hydrogen peroxide generated on-linevia oxalate by the catalytic effect of oxalate oxidase in spinach in the flow cell. The biosensor responds linearly to oxalate concentration in the range of 4 0×10^-7 to 1 0×10^-4 mol/L, and the detection limit is 2×10^-7 mol/L. A complete analysis could be performed in 1 min with a relative standard deviation of 3 7% for 1 0×10^-5 mol/L oxalate(n=7). The system is stable for over 200 times determinations and has been applied in urine samples.