In this work,an orthogonal separation method was developed for the separation of lycopene isomers based on the combination of low temperature(L-T) C18 column and C30 column.As the temperature decreased to -20 ℃,the resolution for the separation of lycopene isomers on a normal C18 column was greatly improved.After investigating the relation of solubility and resolution,seven kinds of lycopene isomers were finally prepared by the orthogonal separation method with their purities all higher than 97%.The loading capacity and purification effect of the orthogonal method for lycopene were much higher than that of the method only based on L-T C18 or C30 column.Then,the obtained all trans lycopene were dissolved in walnuts oil,black seed oil,almonds oil,grape seed oil,pumpkin seed oil and peach kernel oil,respectively,and heated at 120 ℃ to study their isomerization.Grape seed oil was regarded as the most valuable solvent for developing lycopene product due to its highest cis/all trans ratio of lycopene isomers after heating.Finally,the stability of cis isomers at 4 ℃ in edible oils was investigated by taking walnut oil as the example.Both the isomerization and degradation of these isomers happened with the increase of storage time.All trans lycopene and(13Z)lycopene were found as the preferential conformations in walnut oil.The obtained results were expected to provide some beneficial information for the development of lycopene product.