Abstract: This study investigated the effects of population density,food,temperature and light in- tensity on the growth and reproduction of D. magna HB,collected,in summer in fish ponds in Wuhan,as well as the methods of breeding and strain maintenance.Results from three years continuous breeding in the laboratory showed that D. magna HB grew and reproduced normally between 15-31℃ when fed fresh green algae.At 31℃,the maximum body length was 3.65 mm and the maximum number of eggs/brood was 26. According to the method recommended by the ISO 6341,the susceptibility of Daphnia magna HB to the standard toxicant,potassium dichromate was determined,24h EC50 was 0.92 mg/L.