Abstract: Several multilayered biaxial weft knitted (MBWK) fabric reinforced composites with different shear angles were prepared by changing the orientation of preform inserting yarns. The thermo-oxidative aging test was designed based on Arrhenius model and Ozawa method. The thermal and physical properties of the samples before and after aging were characterized by mechanical properties, DSC, FTIR and DMA tests. The experimental results show that: With the change of yarns’ shearing angle, the composite mechanical properties retention rate after thermo-oxidative aging is also significantly different, because the post curing will occur for the vinyl ester resin in the thermo-oxidative aging environment. Therefore, the bending modulus of the composite materials in the aging process presents downward trend after increased first, and the tensile properties are affected by the reinforcement structure. The degradation of adhesion strength at fiber/matrix interface makes the tensile modulus decrease continuously during the aging process. With the aging time prolongation, the curing degree of resin increases gradually, and the glass transition temperature T_g increases gradually. The peak value of energy storage modulus increases at the initial stage of aging due to molecular chain crosslinking, while decreasing of the peak value is caused by molecular chain fracture at the later stage of aging.