Abstract: The biodegradable composites reinforced with kenaf fibers were prepared by press forming , and the flexural modulus of the composites was investigated in view of the effect of the fiber volume f raction , length and orientation dist ribution. Based on the COX shear-lag and the characteristic of the kenaf fiber compression , a modified modelwas put forward and the flexural modulus was predicted. The experimental result s show that the flexural modulusincreases with the increase of the fiber volume f raction , length and orientation factor. SEM observations reveal thatthe cellular st ructure of the raw kenaf fiber is compressed and becomes more rigid and denser af ter fabrication. Thiscould cont ribute to the improvement in the flexural modulus. With the modified shear-lag model incorporated withthe fiber compress ratio , the predicted result s agree well with the experimental values.