The work aims to study the effect of MAH mass fraction on the tensile strength of LDPE-g-MAH/PA6 blend. When MAH mass fractions were respectively 0.03%, 0.05%, 0.1%, 0.2% and 0.3%, infrared spectroscopy and scanning electron microscope, etc. were used to research the effects of MAH mass fractions on LDPE-g-MAH grafting ratio, viscosity and morphological characterization, as well as on the tensile strength of LDPE-g-MAH/PA6 blend. The results showed that when the MAH mass fraction was 0.1%, the grafting degree of MAH monomer grafted LDPE was the highest, with the grafting ratio of 4.9%, and the tensile strength reached its maximum. From all above, the conclusion is that the mixing property and tensile strength of LDPE-g-MAH/PA6 are the best when the MAH mass fraction is 0.1%.