Breeding ecology of Lesser Whitethroat (Sylvia curruca) was studied in Hongjiannao (N 39°04′21″~39**°04′43″,E 109°53′12″~109°53′40″) of Shaanxi Province from April to July in 2012 and 2013. The results showed that the Lesser Whitethroat (Sylvia curruca) arrives at this breeding area in late April and nesting on branches of Artemisia ordosia, Sabina vulgaris and Hippophae rhamnoides in early May, the cup-shaped nests were upward and made of catkin, deadwood and hay. The nest parameters were measured in 33 of 35; external dimension of nest, internal dimension of nest, nest depth and nest height were 9.62±0.227 cm, 5.21±0.084 cm, 5.05±0.160 cm, 9.03±0.185 cm, respectively. The nest height above ground was 24.91±1.084 cm and located in lower part of vegetation (about 1/3). The mean clutch size was 4.83±0.081, The weight, length and breadth of eggs were 7.49±0.021 g, 17.27±0.057 mm and 12.86±0.080 mm, respectively. Incubation lasted for 11~13 d, Hatching and survival rate of Lesser Whitethroat were 93.7% and 91.4%. The morphological parameters of nestlings were suitable to fit to Logistic curves. The height, canopy and cover area of individual vegetation were the key factors for nest-sites selection, the foul weather and human disturbation were important factors to affect breeding success.