Disclosed are a method of measuring concentration distribution of boron for boron neutron capture therapy (BNCT) using magnetic resonance imaging (MRI) alone and a treatment planning method for BNCT. The methods include (a) acquiring an anatomical image of a patient and measuring a boron concentration from magnetic resonance (MR) data, (b) extracting a boron concentration change prediction parameter of the patient and predicting the concentration over time, (c) calculating and verifying a boron distribution prediction value estimated by boron imaging and spectral analysis, and (d) deriving an optimal time for BNCT based on the verified results.