Since the 20th century, urban areas have rapidly expanded worldwide, and some bird populations have changed their nesting characteristics in urban habitat that completely differed from their natural habitats. However, we still have limited knowledge about the impact of urban environment on bird nesting. Both the positive and negative urbanization effects on birds nesting and breeding outputs have been reported. In order to understand the plasticity of bird nests in urban environment, this study measured 10 nesting (e.g., size and shape) and site parameters (e.g., distance from the ground and roof) of barn swallow (Hirundo rustica) from both urban and rural habitats in Harbin, Heilongjiang Province in 2016 and 2019. We aimed to explore:(1) Did any difference exist in nest characteristics between rural and urban habitats? (2) Did the nest characteristics of barn swallow vary between years? We also provided the theoretical basis and reasonable suggestions for protection of urban barn swallow populations. Kruskal-wallis rank sum test and Wilcoxon rank sum test were used to compare and analyze the differences between urban and rural nests and inter-annual characteristic parameters, and Linear Discriminant Analysis (LDA) was performed on characteristics of urban and rural nests in 2016 and 2019. The results showed the difference between urban and rural areas:(1) compared with nests in rural habitat, urban nests were farther from the roof and closer to the ground relatively (P<0.05), and to avoid bad weather or predation may caused rural nests much higher from grounds and closer to roofs which built outside doors; (2) The nests in urban were much shallower than those in rural habitat (P<0.05), and may correlate with saving earths or times invested in building nests which above supporting substrates. As for difference from 2016 to 2019, (3) both urban and rural nests became deeper with larger radius (P<0.05) which assumed that because the barn swallows reused the old nests with repairs, which made the nests became bigger and deeper with the using time increased many. In terms of these results, we assumed that the stairway corridors in urban buildings provided a relatively closed and safe environment for barn swallows, and the old nests and abundant anthropogenic upholders provided suitable nesting sites for them, which could save the breeding costs of bird parents on the nest. Nevertheless, we should also pay great attentions on the ecological traps caused by closed doors and windows, limited resources, and human interference which can decrease the birds' breeding success.