Urban landscapes are highly dynamic. Understanding the within-city dynamics in land cover and land use is important. Previous studies have largely focused on the changes of specific land use type (impervious surface, urban vegetation etc.) resulted from urban sprawl on large or medium scales. However, research on quantifying the urban dynamics on block scale is lacking. Taking Shenzhen as a case study area, this paper aims to use the land cover thematic maps interpreted from very high-resolution remote sensing images to quantify the urban dynamics within city at street block level. The results showed that: (1) there was high dynamics at street block level in Shenzhen, which was manifested as that the blocks with dynamic changes account for 14.93%. The hotspots of degree of urban dynamics were distributed in Nanshan, Baoan and Yantian district. (2) The contribution of dynamic changes (CDC) was significantly different between different land use changes on block scale. For all blocks, the CDC of change from woodland to bare soil was the highest (12.59%). In addition, CDC of land use and land cover changes which mainly resulted from urban renewal was high. For example, CDC of changes from other impervious surface and building to bare soil were 6.20% and 5.59%, respectively. In addition, the land use intensity of different block was obviously different. The blocks with increased land-use intensity were mostly distributed in the periphery of the city, while the blocks with decreased land-use intensity were mostly distributed in the interior of the city. (3) The relationship between dynamics of block and block size was nonlinear. With the block size increasing, the dynamics of block decreased sharply and then the decreasing trend became flat. Our study revealed the characteristics of the land use dynamics at street block level in Shenzhen, and it would provide a reference for urban planning and ecological space management.