In this paper, the tensile performance of 3D printed continuous fiber reinforced thermoplastic materials is investigated. Continuous carbon fiber and PetG are employed as reinforcement and matrix, respectively. Pure solid plastic infill, unidirectional fiber infill, and +45/-45 fiber infill patterns specimens are selected for printing and testing. Where the printed composite specimens have the same fiber volume fraction of 25%. As a results, the printed continuous unidirectional fiber composite material with has 15 times higher stiffness than that of the printed pure plastic material. Besides, with the same fiber volume fraction, the unidirectional fiber infill specimen has 1.5 times higher stiffness than that +45/-45 fiber infill specimen. Those results are close to conventional composite materials, however, they are smaller. The microscope images show some intrinsic uncertainty in the microstructure of 3D printed part such as voids, imperfection, and the gap between fiber bundles could be the source of variability which decrease the mechanical properties.