Carbon fiber tape reinforced thermoplastics (CTT) are highly promising materials due to their high formability, mechanical performance, and recyclability; however, CTT is known to have a larger standard deviation of mechanical properties and lower out-of-plane shear modulus than metal materials. In this study, a topology optimization was conducted considering the mechanical property deviation and anisotropy of CTT. A CTT tensile simulation model was used to formulate the relationship between the material size and coefficient of variation. The simulation result showed that a lower specimen length and thickness caused a larger variation of elastic modulus due to the non-uniformity of mechanical properties. A penalty parameter was introduced in the topology optimization model based on the idea of effective length and thickness in the structure. Different optimal structures with thicker parts were obtained when a penalty parameter was considered; however, some rotation angles in the optimum structure were complex and a large threshold for penalty parameter caused bad convergence.