This paper deals with the results of an e$periment to cultitrate Brachionus plicatilis by using beer yeast Saccharomycas cerevisiac. The cultivating water used is diluted solutim of concentrated seawater from Fengaian Saltern. Its specific gravity is 1 .015 (i.e. salinity is 19.61‰)，pH jralue is 8.44-8.46，and 8.65 ppm in CDD_Mu.The results are summarized as fallorns: 1.The optimum inoculational density of the rotifer is about 14-70 ind./ml at 25℃. 2 .The feeding quantity pan notably affact the pH value, dissolved oxygen,chemical oxygen demand and other entriromental factors in the eultevating water, but there wotald be no any significient impacts far propagation of the rotifer if under well aerated condition. 3,The feeding quantity is determined on the rate of the fatal wet w eight of the rotifer, with the weight of the yeast. It varies with the change of water temperatures.The experiment shows that the optimum feeding rate is 3 when the water temperature is 30℃. If the density of the rotifer is maintained at 200 ind./ml, a high and stable yield would be expected. In our experiment, the yield per day of the rotifer reached to 470 thousand in a 3 Titre volume cultural battle for seventeen days, and the maximum value per day reached to 6fifi thousand. 4 .The emulsified fish liver oil is also used to feed the rotifer beside the yeast,the oil became minute granules with the size from 1μ to 20μ, they can be aasily swallowed by the rotifer. In feeding of fish liver ail the concentration under 80 ppm(or the accumulation don't beyond 10d ppm)，there will do no harm for reproduction of the rotifer. But tha accumulative concentration excess 120 ppm, the reproduction would be restrained.