The structure formation of superalloys is very complicated because of their multicomponent composition and multiphase transition processing. Duo to the limitation of some pre-conditions, the structure formation can not be accurately determined by thermodynamic calculation method. Knowledge about the structure is critical for the design of the following heat treatment process. In this work, a single crystal (SC) sample of superalloy CM247LC was directional solidified in a labor Bridgman furnace with a pulling rate of 0.2 mm/min and then water quenched, to investigate the solidification sequence including MC carbide and γ/γ′-eutectic. It was observed that the γ-phase is firstly formed in the form of dendrites; it is then followed by the homogeneously precipitation of MC carbides from the liquid behind dendrite tips. Near the end of solidification the interdendritic residual liquid transits into γ/γ′-eutectics. It is interesting to found that the γ/γ′ eutectics do not nucleate on the existing γ -phase, but preferably on the MC carbides which have completely different chemical composition and crystal structure. The result of EBSD examination indicates that the γ/γ′ eutectics formed on the MC substrates have random crystal orientations compared to the SC γ -matrix, exhibiting the misoriented multi-crystal microstructure in the so called "single crystal" superalloy casting.