Compounds with the A15 structure have attracted extensive attention due to their superconductivity and non-trivial topological band structures.We have successfully grown Nb3Sb single crystals with the A15 structure and systematically measured the longitudinal resistivity,Hall resistivity and quantum oscillations in magnetiza-tion.Similar to other topological trivial/nontrivial semimetals,Nb3Sb exhibits large magnetoresistance(MR)at low temperatures(717％,2K and 9T),unsaturating quadratic field dependence of MR and up-turn behavior in pxx(T)curves under magnetic field,which is considered to result from a perfect hole-electron compensation,as evidenced by the Hall resistivity measurements.The nonzero Berry phase obtained from the de-Hass van Alphen(dHvA)oscillations demonstrates that Nb3Sb is topologically nontrivial.These results indicate that Nb3Sb su-perconductor is also a semimetal with large MR and nontrivial Berry phase.This indicates that Nb3Sb may be another platform to search for the Major ana zero-energy mode.