This paper reports a new type betavoltaic (BV) microcell based on intrinsic p-type semiconductive single-walled carbon nanotubes (s-SWCNTs). Our device composes of Au and Ti asymmetrical electrode pairs with s-SWCNTs laid over them forming Schottky junction with Ti and ohmic contact with Au. SWCNT bundles were self-assembled between Au and Ti electrodes by Dieletrophoretic (DEP) technique, and metallic SWCNTs (m-SWCNTs) were selectively eliminated by current-induced electrical breakdown method. 3.3mCi/cm 2 thin-film radioisotope 63 Ni serves as beta particles source, with 100-year half-time and low toxicity. Test results show that SWCNTs BV microcell has the open circuit voltage (V OC ) of 26mV, short circuit current density (J SC ) of 2.19μA/cm 2 and energy conversion efficiency (η) of 5.20%.