Abstract: Multiple melting behaviour of nylon 610 has been studied by differential scanning calorimetry (DSC) and wide angle X-ray diffractometry (WAXD). Three melting peaks were observed on the DSC thermogram. According to both the partial inelting and the fractional melting viewpoints, the respective origin of the peaks was discussed. From the results obtained by programmed heating, isothermal crystallization and specific volume measurement, the equilibrium thermodynamic parameters T_m and △H_m of nylon 610 were estimated to be 517.6K and 211.7J/g respectively.