Abstract: A method for characterizing the melting process of chocolate quickly and accurately by low-field nuclear magnetic resonance technology(LF-NMR)with online control of sample temperature module was presented. Effects of cocoa content on the melting temperature of chocolate was investigated with this method. Characterization of the relaxation time(T₂)corresponding to the movement of liquid oil molecules of chocolate was conducted by continuously controlling and detecting the temperature of the sample online. The melting process of four brands chocolate with different content cocoa was evaluated. The results indicated that the T₂ value increased with the temperature,the movement of liquid fat in chocolate increased,and the melting temperature increased with the increase of cocoa butter and crude fat content. It is the first time to detect the chocolate melting process online,and directly and accurately measure the melting temperature of chocolate by using LF-NMR online temperature control analysis system,which provides reference for the production quality control of chocolate.