Recently, diffusion-weighted imaging (DWI) has become essential for diagnosing acute cerebral infractions and detecting lesions via magnetic resonance imaging (MRI). Investigations using phantoms have been performed to evaluate the optimizing parameters before clinical practice. However, there have been no studies on extracting appropriate phantom materials. It is known that the apparent diffusion coefficient (ADC) changes with temperature. To extract optimal materials from polyethylene glycol, sucrose, and dextrin in previous studies, evaluations were performed using ADC with temperature change and signal-to-noise ratio (SNR) . Results of comparison with difference between true and measured values depend on the Stokes-Einstein formula for ADC change with temperature change; the highest value was obtained for polyethylene glycol. In the SNR measurement, when the temperature increased, the rate of change of ADC decreased. Polyethylene glycol showed the highest value. According to these results, it can be concluded that polyethylene glycol can be extracted when nearest to true value and when there is a high SNR, thus making polyethylene glycol the most suitable material for diffusion-weighted image phantoms.