We explore for the spin liquid state. Recently, the theoretical studies suggest that not only the frustrated lattice but also a structural fluctuation and disorder are important for the spin liquid state. The spinel titanate MgTi2O4 undergoes the structural transition from the cubic to tetragonal phase. The Ti ions are dimerized and form the spin singlet pairs. In the Mg-substituted Mg1+xTi2-xO4, though the tetragonal phase collapses, the Ti structural fluctuation remains and can induce the spin liquid state. In our previous study (EN 1770008), no muon-spin precession was observed at the lowest temperatures in Mg1.25Ti1.75O4 (x=0.25), suggesting no sign of a long-range magnetic order. In this proposal, in order to clarify the mechanism of this spin liquid state, we would like to suggest to measure the three samples in different x at 0.3K~300K and request six days beamtime.