The invention provides a method for cultivating smallanthus sonchifolius. The method comprises the following steps: firstly, seedball segmentation, wherein the seed bud weight is 30-50g; secondly, seed bud treatment, wherein a seed bud is soaked in whitewash for 5 min and subjected to seed soaking after drying; thirdly, seedling culture, wherein the seed bud after treated in the second step is planted in a nutrition pot which is sequentially filled with 30 parts of ceramic granules, 40 parts of composite soil and 30 parts of sandy soil from bottom to top, the composite soil is formed by mixing humus with sandy soil in a weight ratio of 1 to 3, the nutrition pot is placed in a greenhouse for culture, and a seedling is obtained for spare when 6-8 leaves grow out; fourthly, transplanting in a field, wherein the seedling obtained in the step three is placed in a seed pit together with the nutrition pot; fifthly, field management, wherein field planting water is watered on the very day of transplanting and comprises bitter melon juice and clean water in a weight part proportion of 1 to 50. The method for cultivating smallanthus sonchifolius is directed at characteristics of smallanthus sonchifolius and has the advantages that steps are simple, operation is facilitated, manpower and material resources are saved, and yield and fruit quality of the northern planted smallanthus sonchifolius are improved.