Laboratory experiments were carried out in the Insectary of Economic Entomology Department Faculty, of Agriculture, Mansoura University, from the beginning of October 2011 tell the end of September 2012 under three constant temperature degrees (15±1, 25±1 and 30±1 C^o) to study the influence of three constant temperature degrees on biological characteristics for the coccinellid predator Rodolia cardinalis (Mulsant) when reared on the third nymphal instars of Icerya purchasi Mask. The obtained results revealed that, the average of the total consumption per larva was 55.96 ± 1.3 individuals, the duration period of the larval stage averaged 30.1±0.56 days. The percentages of the mortality were 20.5, 13.9, 6.9 and 5.6 % during the four larval instars respectively when this predator reared on I. purchasi under constant temperature of 15±1 C^o and 70±5 %. The predator female fed on a total average of 389.28±5.7 individuals, during the longevity period of 66.07±3.7 days. The number of deposited eggs per predator female was averaged 156±3.9 eggs. The predator male consumed a total average of 210.75±3.42 individuals. Meanwhile the data showed that, the average of the total consumption per larva was 107.53±6.2 individuals, when this predator reared on I. purchasi  nymphs under constant temperature of 25±1 C^o and 70±5 %, the duration period of the larval stage averaged 14.37±1.6 days. The percentages of the mortality were 13.4, 9.1, 4.5 and 3.7 % % during the four larval instars respectively. The predator female fed on a total average of 348.82 ± 8.56 individuals, during the longevity period of 42.5±2.1days. The number of deposited eggs per predator female was averaged 455.79±10.17 eggs. The predator male consumed a total average of 201.74 ± 5.96 individuals. The obtained results revealed that, the average of the total consumption per larva was 87.16±4.6 individuals, the duration period of the larval stage averaged 9.24±1.95 days. The percentages of the mortality were 14.2, 10.4, 5.7 and 4.5 % during the four larval instars respectively when this predator reared on I. purchasi under constant temperature of 30±1 C^o and 70±5 %. The predator female fed on a total average of 248.30±7.96 individuals, during the longevity period of 32.15±1.92 days. The number of deposited eggs per predator female was averaged 310.75±8.56 eggs. The predator male consumed a total average of 176.35±5.46 individuals. Statistical analysis showed significant differences between the duration periods as well as the average of total consumption per larvae for the larval stage under the three constant temperature degrees. Meanwhile the statistical analysis cleared significant differences between the longevity period for female and male as well as the average of total consumption and the number of deposited eggs per female and the three constant temperature degrees. In conclusion the optimum temperature for mass rearing of this predator was 25±1 C^o because the number of deposited eggs per female the feeding capacity was the highest in comparison with the other temperature degrees.