Urban agriculture (UA) is an important socio-ecosystem in the urban–rural ecotone. Previous studies focused on the production and leisure service of UA, ignoring the evaluation of ecological performance, which hindered the comprehensive performance of UA. In order to better connect with urban planning, this paper selects 37 urban agricultural parks (UAPs) and 10 urban parks (UPs) in Beijing as the research objects. It discusses the ecological performance from the effect of reducing heat island effect and enhancing the fractional vegetation cover (FVC). The results showed that UAP has better external cooling effect and wider cooling range. The index of FVC showed different differences according to different seasons of UAPs, but the seasonal change of FVC of UAPs and UPs is consistent. It can be assumed that UA can be regarded as ecological land and provide ecological performance together with UPs in the following situations. First, the supply function of UA is needed in the region, and the regional land use is very tight, which can be considered. Secondly, UA can be considered when there is a need to adjust the heat island effect through the park, because UAPs have a wider range of external influence and better effect. This study examined the difference in ecological performance between UAPs and UPs and provided a basis for the proposition that UA can be considered as ecological land in planning.