Jellyfish blooms cause problems worldwide,and their outbreaks have been reported at unprecedented rates in the recent decades. The blooms of Aurelia spp. have become increasingly prominent worldwide since the end of the 20th century, causing serious damage to fisheries, marine ecosystems, and coastal power plants. Environmental factors that control the size of jellyfish populations are not well understood ; however, many researchers suggest that global warming, water pollution, and overfishing may be the main factors. Many scyphozoan species, including Aurelia spp.,have a benthic polyp stage. This stage is an important part of the life cycle of Aurelia spp.,because polyp clones can increase their population size by asexual reproduction,providing the opportunity to increase the medusa population by the production of many ephyrae through strobilation. Environmental factors that affect the asexual reproduction rates include temperature, salinity, light, and food. In this study, polyps of Aurelia sp.1,collected from Heishijiao,Dalian, China, were tested using various environmental factors : (1) 11 different temperatures (0,2.5,5,7.5,10, 12.5,15,17.5, 20,22.5, and 25 ℃ ) at salinity 28; (2) 14 different salinities (7.5,10,12.5,15,17.5, 20,22.5,27.5, 30, 32.5, 35,37.5,and 40) at ambient temperatures (1525 ℃ ) and natural light conditions; (3)5 different light intensities (0,200,400,600,and800 lx) at 2025 ℃ and a 10-h light/14-h dark photoperiod; and (4) 5 feeding frequencies ( 1 time/1 day, 1 time/2 days, 1 lime/8 days, 1 time/16 days, and no feeding, which represent 8.3,4.2, 1.0,0.5, and 0 mug C per polyp/day) at1525℃. Asexual budding was strongly affected by temperature, feeding frequency, and light intensity, but it was not affected by salinity. The production of new buds increased dramatically with increasing temperatures, particularly in the range of 12.525 ℃. The asexual reproduction rate was the highest at salinity 22.5, and it gradually decreased as the salinity increased or decreased ; however, the statistical results did not show any significant influence. Dark or dim light conditions greatly favored asexual reproduction, while bright light inhibited it. Asexual budding significantly decreased with decreased feeding frequency; a total of 959 buds were produced by feeding 1 time per day, and the number of buds decreased to only 13 by feeding 1 time per 14 days during the 60-day experiment. No polyps died even under no feeding conditions, which demonstrated that Aurelia sp.1 polyps have a strong resistance to starvation. Survival was high in all the treatments, except in the salinity range of 7.512.5 ; this indicated a wide tolerance to environmental conditions. All these results indicate that the environment of the Bohai Sea and Yellow Sea is suitable for the survival and reproduction of Aurelia sp.1. We suggest that increased temperatures because of global warming, increased abundance of zooplankton prey because of eutrophication, and increased seawater turbidity caused by industrial pollution may be responsible for the prominent blooms of Aurelia sp.1 medusae in the coastal waters of the Bohai Sea and Yellow Sea.