Thermal history of Rhea from the beginning of accretion is investigated. We developed a numerical model of convection combined with the parameterized theory. Large scale melting of the satellite’s matter and gravitational differentiation of silicates from ices are included. The results are confronted with observational data from Cassini spacecraft that indicate minor differentiation of the satellite’s interior. We suggest that partial differentiation of the satellite’s interior is accompanied (or followed) by the process of light fraction uprising to the surface. The calculation indicates that the partial differentiation of the matter of the satellite’s interior is possible only for narrow range of parameters. In particular, we found that the time from the formation of CAI (calciumaluminum rich inclusions in chondrites) to the end of accretion of Rhea is in the range of 3–4 My.