||CVD growth is a feasible method to produce 2D transition metal dichalcogenides (TMDs) in large area. Despite its benefit in controlling crystal structure and number of layers of 2D TMDs, CVD process mostly relies on the thermodynamic equilibrium, yielding specific shapes of the as-grown domains which are the most stable. In this context, numerous efforts have been devoted to drive the anisotropic CVD growth of 2D TMDs by adopting catalytic impurities. Here, we present a method to facilitate 1D growth of 2D TMDs using faceted sapphire substrates. Single crystalline MoSe2 domains grow directionally along the facets of substrate with high aspect ratio more than 10. A systematic study confirms that the shape of MoSe2 domain shows dependencies on the growth temperature, precursor amount, system pressure, etc. This work suggests a novel route to design and fabricate anisotropic 1D monolayer of 2D TMDs, important for the integrated electronic/optoelectronic device applications.