The effect of heat treatment in superalloy CM247LC on tensile properties at various temperatures has been investigated. In the case of equiaxed poly-crystal specimen, the aged condition (HTA condition) has higher strength than the solution treated and aged condition (HTSA condition) at low temperature. The HTSA condition exhibits higher strength than HTA condition in directionally solidified specimen in all temperature range. Shearing of γ´ particle is a principal deformation process at the low temperature, and cutting of fine secondary γ´ particle plays important role in the early stage of deformation in the HTA poly-crystal specimen. Tangles of short misfit dislocations form at the γ/γ´ interface during the high temperature deformation due to the partial loss of coherency at the interface. The rafting of γ´ increases tensile strength of the HTSA specimen at and above 871°C.