In this paper, chopped strand mat (CSM) and Woven were used as the major reinforcement components of composite materials. The fiber was changed to verify the difference in strength of each fiber. Besides, vacuum was also used to confirm its role in composite fabrication procedure. In addition, 0.1 wt.% multi-walled carbon nanotubes (MWCNTs) were added in unsaturated polyester resin (UPR) as the high potential candidate to improve properties of composite structure. Flexural test was conducted to find the strength and modulus of all specimens. Consequently, Woven shows almost two times higher than CSM in both strength and modulus, while combination of CSM and Woven was shown as the average values of each fiber. The vacuum was assisted hand lay-up fabrication method, so it also represents a good effect for composite structures such as 21.98 % and 22.72 % increase in strength for CSM and Woven, respectively; a small increase in flexural modulus for both of them (2.02 % and 3.08 %, respectively). Meanwhile, combination of CSM and Woven has much higher properties (87.15 % increase in strength, 67.81 % increase in modulus). However, from this experiment MWCNTs have not indicated a good impact on flexural strength, even though they have a little positive effect on flexural modulus of composite structure.