Recent media reports have warned that carambola with high oxalic acid content has high health risk, therefore, in order to minimize consumer worries, producing high quality and low oxalic acid carambola has become primary work. The oxalic acid content and glycolate oxidase activity were analyzed among the tart and sweet carambola, and they were indicators for breeding screens. Results indicated that the oxalic acid tended to decrease during maturation in both types of carambola. However, regardless of maturity, the oxalic acid content in tart carambola was always higher than that in sweet carambola. Glycolate oxidase activity in leaves and fruits of tart carambola was also higher than that in sweet carambola.