In this work, the effect of HDPE and PBS blend ratio on mechanical properties and phase morphology of the blend was investigated. HDPE/PBS blends were prepared at HDPE content of 20, 30, and 40 wt.% via melt mixing process and then molded using an injection machine. HDPE/PBS blend was an immiscible blend with a type of dispersed in matrix morphology and coalescence phase morphology depending on HDPE content. The blend morphology of 20 wt.% HDPE/PBS blend was a type of spherical domain dispersed in the PBS matrix. As increase HDPE content, the dispersed HDPE particles became larger and the shape turned into worm-like and elongated structure. In addition, at 40 wt.% HDPE, coalescence phase morphology was obtained. It was found that the PBS blends containing 30-40 wt.% HDPE did not show yield point; they exhibited brittle failure behavior. For tensile properties, yield strength and stress at break of HDPE/PBS blend gradually decreased with increasing HDPE content. However, addition of HDPE into PBS matrix resulted in an increase of Youngs modulus of the PBS blend. Impact strength of the blends was much lower than that of neat PBS but the impact strength of the blend insignificant changed with 30-40 wt.% HDPE comparing to that with 20 wt.% HDPE.