The cross-linked starch/polycaprolactone (SPCL10) and starch/ polycaprolactone (SPCL12) blends were prepared, characterized and used as carbon source and biofilm support for biological nitrate removal. The denitrification performance using different polymers as carbon source was compared. The results showed that SPCL10 and SPCL12 had similar performance on water absorption (about 21%) and leaching capacity. FTIR spectra confirmed the cross-linking reaction between starch and PCL. SEM displayed a thermoplastic nature of SPCL10 and SPCL12. These blends could serve as solid carbon source and biofilm support for biological denitrification, the acclimation time of microbial biofilm on the surfaces of SPCL10, SPCL12 and PCL were about 2 d, 2 d and 16 d, respectively. The average denitrification rates were 0.0216, 0.0154 and 0.0071 mg NO3-N/(g*h) for SPCL10, SPCL12 and PCL, respectively, the effluent NO2-N concentration was below 1 mg/L in all cases. The phenomenon of ammonia formation was observed, but ammonia concentration was below 0.5 mg/L.