Electron Spin-Echo (ESE) measurements on mixed-stack charge transfer compound tetrathiafulvalene (TTP)-chloranil (CA) are reported. Below Neutral-Ionic transition temperature, the ESE signals related to the spin solitons were observed. Comparing the phase memory time with the inverse of the EPR line-width, it was found that a crossover from fast motion of the spin solitons to slow motion took place around 70K. In addition ,the spin relaxation measurements suggested the thermal fluctuation of the dimerized lattice above 60K.