Up-conversion emission spectra of Er(3+) singly and Er(3+)/Yb(3+) co-doped CaIn(2)O(4) were investigated under a 980 nm diode laser excitation. Double intense UC emission bands in green and red region are observed in Er(3+)/Yb(3+) co-doped CaIn(2)O(4), resulting in the tunable ratio of red to green and the chromaticity coordinates by adjusting the concentration of Er(3+) and Yb(3+). Based on the pump power dependence, the possible UC mechanism in Er(3+)/Yb(3+) co-doped CaIn(2)O(4) was proposed, and lifetime measurements were also carried out to support our proposal.