Abstract:This paper deals with the distribution, category, ultrastructure and lammelar changes ofplastids in the stem of the dodder at four development stages. The qualitative assay wasmade oil the photosynthetic capacity of each period with spectrofluorimeter. The results are asfollows: The dodder is a semi-parasitic plant because it contains chlorophyll and chloroplasts whichare capable of photosynthesis. Chloroplasts exist only in phloem parenchyma, and containwell developed lammelar system during the development of haustoria. In this plant, the lammelar system has a rather unusual arrangement, similar to that of semi-parasite Viscum albumbut different from that of the typical seed plants. “Green amyloplasts” (GA) were observedin cortical parenchyma. The photosynthetic and parasitic ability of the dodder is the strongestin the seedling stage when the best effective control on dodder can be obtained.