In this work, the thermal expansion behavior of short carbon fiber/epoxy composites was investigated with respect to fiber length and fiber volume fraction. The effective coefficient of thermal expansion of short carbon fiber/epoxy composites was calculated based on the Halpin-Tsai equation for moduli and the linear coefficient equation. From the investigation, it has been found that the coefficient of thermal expansion is more dependent on fiber volume fraction than fiber length. Therefore, the ferrule for optical connector that has the compatible coefficient of thermal expansion with the optical fiber war manufactured with short carbon fiber/epoxy composite by controlling the fiber volume fraction.