Urban residential greening provides opportunities for social integration and 8 physical exercise. These activities are beneficial to promoting citizens' mental health, 9 relieving stress and reducing obesity and violent crimes. However, how to measure 10 the distribution and spatial difference of green resources in urban residential areas 11 have been controversial. This study takes the greening of urban residential units in 12 Shenzhen City as its research object, measures the various greening index values of 13 each residential unit, and analyses the spatial distribution characteristics of residential 14 greening, regional differences and influencing factors. Large sample of street view 15 pictures, urban land use and high-resolution remote sensing image data are employed 16 to establish an urban residential greening database containing 14,196 residential units. 17 This study proposes three greening indicators, namely, green coverage index, green 18 view index, and accessible public green land index, for measuring the green coverage 19 of residential units, the visible greening of surrounding street space and the public 20 green land around, respectively. Results show that (1) the greening level of residential 21 units in Shenzhen City is generally high, with the three indicators averaging 32.7%, 22 30.5% and 15.1%, respectively; (2) the types of residential greening differ per area; 23 and (3) the level of residential greening is affected by development intensity, location, 24 elevation and residential type. Such findings can serve as a reference for improving 25 the greening level of residential units. This study proposes an accessible public green 26 land index as a measure for the spatial relationship between residential units and 27 surrounding green spaces. It suggest that future green space planning should pay more 28 attention to the spatial distribution of public green land, and introduce quantitative 29 indicators to ensure sufficient public green lands around the walking range of 30 residential areas. 31 Key words: green coverage index; green view index; accessible public green land 32 index; greening characteristics; residential units; residential greening 33 1. Introduction 34 Urban greening, such as woodlands, shrubs, grasslands and other green spaces, is 35 a widely recognised element of urban landscapes [1,2]. The ecological effects of 36 urban greening include carbon sequestration, air purification, heat island effect 37 alleviation and stormwater runoff filtration and reduction [3,4]. Greening in 38 residential and surrounding areas is an important part of urban greening. Residential 39 urban greening provides opportunities for social integration and physical exercise, 40which are beneficial to promoting citizens' mental health, relieving stress and 41 reducing obesity and violent crimes [5,6]. 42In comparison with urban parks, street greening and neighbourhood trees play 43 more important roles in the lives of residents. They form green corridors in residential 44 areas and s...