The magnetic flux density inside a Metglas sheet is much higher than that of the applied external magnetic field due to its high magnetic permeability, which is known as the magnetic flux concentration effect. Magnetic flux concentration of Metglas as a function of its sheet aspect ratio (width/length) was investigated for Metglas/Polyvinylidene fluoride (PVDF) laminar composites. Both the simulations and experimental results suggest that the magnetic flux concentration effect is markedly enhanced when the aspect ratio of a Metglas sheet is reduced. Consequently the magnetostriction of Metglas and the magnetoelectric (ME) voltage coefficients of the laminar composites are enhanced. The ME voltage coefficient for a laminar composite with a 1 mm wide and 30 mm long Metglas sheet (25 μm thick) is 21.46 V/cm•Oe, which is much higher than those reported earlier in similar laminar composites without making use of the flux concentration effect. The results demonstrate an effective means to significantly enhance the sensitivity of the magnetostrictive/piezoelectric composites as weak magnetic field sensors.