Lattice strain effect on structural evolution in multi-component olivine is investigated by ex-situ X-ray diffraction analysis with different metal composition in lithium battery system. The multi-component olivine shows partially two-phase reaction as Mn substitution increases, and this structural evolution cannot be explained by only established atomic interaction model. It is expected that the phase behavior relates to not only atomic interaction but also lattice strain in multi-component olivine. We find that the Mn-rich multi-component olivine has higher lattice strain due to its Jahn-Teller effect of Mn3+, which induces phase segregation. The in-depth study on phase behavior of multi-component olivine will provide insight for designing better performing Li rechargeable batteries and helping to understand on intrinsic electrochemical problems.