Natural fiber spun yarns are anticipated for use in reinforcement of composite materials because natural fibers are environmentally friendly. The form of the spun yarns is unidirectional, so that a great increase in mechanical properties is also anticipated, as comparedto randomly oriented short natural fibers. In this study, a continuous ramie spun yarn/PP composite tape wasproduced by developing multipin assisted resin impregnation (M-PaRI) process (in ref.4), acontinuously producing method, in which a die and a roller system following M-PaRI process were newly set. Tensile tests were conducted to measure mechanical properties of the resultant composite tapes. Results showed that the tensile strength of the composite tapes was lower than thatof the composite strands described in ref.4. However, the elastic modulus of the composite tapes showed a higher value than that of the composite strands, exhibiting less statistical variation in the elastic modulus as well. Furthermore, using the least squares method and the first-order second-moment (FOSM) method, a reliability theory, the present study examines the reasons why the tape's elastic modulus can change into a reliable property.