Taking Shenzhen subway as an example, we use Baidu Heat Map to construct a system to evaluate vitality of station service area through heat average and heat coefficient of variation. Station service area, which accounts for 15% of Shenzhen municipal area, has 38%~ 50% of the city population from 7: 00 to 23: 00, less population gather at night and more during daytime. The 166 service areas can be classified into four groups: low-balance mature areas, low-balance developing areas, high-balance mature areas and high-balance developing areas. Their vitality characteristics are quite relevant to built environment. Mature areas have higher development density. High-balance areas have higher land use mixture. Station service areas with large-scale urban village are more likely to show high-balance. The evaluation can be beneficial to adopting available strategies for different types of station service area, and shed light on trancit oriented development (TOD) planning and design.