The study of metakaolin-lime hydration process is of great interest in the field of building materials technology.This study aimed to investigate experimentally the physicochemical properties of pastes containing metakaolin (MK) and lime as activator. MK was produced by calcining Kalabsha kaolinite clay (Aswan, Egypt) at different calcination temperatures 700,800,900 and 1000^oC for 2 hr. Five mixes were prepared by partial substitution of MK by 5,10,15,20 and 25% wt CaO ( from CaCO₃) by weight, then hydrated up to 90 days . The characteristics of prepared specimens were investigated by measuring compressive strength and total porosity. The hydration kinetics were evaluated by determination of free lime contents. The change in phases was investigated by IR technique. The morphology and microstructure of hardened pastes were investigated by scanning electron microscopy (SEM) tests. The results show that, partial substitution of burnt kaolinite clay at 900^oC with 15 % CaO improves the hydraulic properties of MK- lime pastes.