[en] Objective: To study the effects of the strength and number of b values on ADC measurements of normal brain. Methods: Seven different diffusion weightings were applied in twenty normal adult brains in diffusion tensor imaging. the brain ADC maps were calculated using seven different combinations of b values based on strength (b₀b₁, b₀b₂, b₀b₃, b₀b₄, b₀b₅) and on numbers (b₀b₆. b₀b₆, b₀b₁b₆, b₀b₁b₂b₆, b₀b₁b₂b₃b₆, b₀b₁b₂b₃b₄b₆ and b₀b₁b₂b₃b₄b₅b₆). The average of the ADC was measured and compared at the caudate nucleus, posterior limb of the internal capsule, thalamus, centrum semiovale, genu of corpus callosum and splenium of corpus callosum. Results: The measured ADC was significantly decreased accompanied with increase of b values (P<0.05), but did not correlated with the b values number (P>0.05). Conclusion: The strength of b values, not numbers of b value influences measurement of ADC, which should be considered in clinical study