The investigation was carried out during two years in citrus orchards in Qalyubia Governorate  2015 – 2016, to study ecological and biological aspects of the Citrus Flower Moth  Prays citri (Millière) (Lepidoptera: Hyponomeutidae). Data illustrated from ecological and biological points of view. Ranjpure lime (Citrus auranifolia) was the most preferred variety (highly susceptible) of infested by P. citri. While lemon (Citrus limon) which is considered as “moderately susceptible" exhibit less preferable to P. citri, but not seen any infested flowers in navel orange (Citrus sinensis) was the lowest preferred variety, throughout the investigation 2015 – 2016. One peak of infestation of P. citri in spring under weather conditions of Qalyubia Governorate. Predatory potential of Chrysoperla carnea (Steph) larvae on citrus flower moth P. citri larvae, under laboratory conditions was highly significant in mean consumption rate of 2^nd  and 3^rd instars The total consumption by the third instar of C.  carnea was significantly than the second instar . Biological results indicated that Female laid eggs both individually 54.6 eggs in average per female, Incubation period lasted 1.07 days, hatchability was 67.7 % in average, Larval and pupal stage period was 6.37 and 5.33 days respectively, female and male longevity lasted 4.3 and 3.6 days respectively. Life cycle 12.77 days while Generation lasted 13.79 days under 29.4°C and 62.7 % RH.