The experiment was conducted in Hemaida ELsohby district , Qalubiya Governorate , Egypt, during two  successive seasons( 2018-2019 and 2019-2020 )to study the effect of some ecological factors (Max ,Min Temperature ,Relative Humidity (RH) and plant age) on seasonal fluctuations of Tetranychus urticae in three strawberry cultivars (Fertona, Felorida and Festival). Results showed that the correlation was significant negative effects of maximum and minimum temperature on the seasonal fluctuations of Tetranychus. urticae movable stage for the three cultivars during both seasons. The correlation between relative humidity and the seasonal fluctuations of Tetranychus. urticae movable had insignificant negative effect stage for the three Cultivars, during the first season 2018-2019, but it had insignificant positive effect in the second season2019-2020. Also, age of plant had significant negative correlation on the population of Tetranychus urticae in the two seasons.