Pyrochlore Y2Sn2O7 nanophosphors codoped with Er3+ (fixed 2 at.%) and Yb3+ ions (2-16 at.%) were synthesized via hydrothermal process followed by heat treatment. We investigate the infrared-to-visible upconversion (UC) luminescence properties of Er-Yb codoped Y2Sn2O7. Upon 980 nm excitation at room temperature, green (at similar to 522 and 544 nm) and red (at similar to 661 nm) UC emissions were observed, which are ascribed to the (H-2(11/2), S-4(3/2)) -> I-4(15/2) and F-4(9/2) -> I-4(15/2) transitions, respectively. It has been found that the Yb3+-doping concentrations have greatly influenced on the UC luminescence intensity and the emission ratio of the red and green in Y2Sn2O7:Yb3+/Er3+ nanophosphors. The tunable emission is due to the energy back transfer from Er3+ to Yb3+ and the cross relaxation between the two neighboring Er3+ ions. It is expected that the achieved single and intense red emission band may have potential application for in vivo bioimaging.