In this work, we have mainly investigated the electrochemical properties of Bi2SiO5 and Bi2O2CO3. They have the different layer structures and the areal capacitance (10.1 mF cm(-2)) of Bi2O2CO3 electrode is 2.9 times higher than that (2.6 mF cm(-2)) of Bi2SiO5 one at 0.1 mA cm(-2). After 4000 cycles, 84% and 81% capacitances are retained for Bi2O2CO3 and Bi2SiO5 electrodes, respectively. Because Bi2O2CO3 has a lower BET area (3.634 m(2)g(-1)) and a higher electrical resistance (5.231 omega cm(2)) than Bi2SiO5(35.13 m (2)g(-1), 2.022 omega cm(2)), their different electrochemical properties have been mainly attributed to the different fine layer structures. For Bi (2)02C0 (3), the anion layers and cation layers are completely separated and the unobstructed passageways form, which would favour to get in and out for ions and improve the capacitance. For Bi2SiO5, the newly-formed Bi-O-Si bonds can improve conductivity, but there is no passageway between the anion layers and cation layers, which does not favour for the getting in and out of ions. This study demonstrates that fine layer structure has a significant influence on the electrochemical properties.