The spinel titanates MgTi2O4 undergo the structural transition to the tetragonal phase. Since the displacement of the Ti ions has two-in two-out configuration, we consider the MgTi2O4 system as one of the candidate for the atomic-displacement-type ice. Below the transition temperature, the magnetic susceptibility decreases. Even in the Mg-substituted Mg1+xTi2-xO4, the reduction of the magnetic susceptibility is also observed in the cubic phase. It is still unclear whether the magnetic ground state is a spin-singlet state or not. We propose mSR experiment on Mg1+xTi2-xO4, and suggest to selecting key samples to clarify the magnetic ground state.