In this study, we calculated the amount of global solar radiation captured by the greenhouses at different latitudes. The energy can be used to heat the greenhouses in winter, hence reducing the consumption of fossil energy for greenhouse heating. A script developed in Matlab was used to calculate the captured amount of global solar radiation from 1 November to 1 March of the next year for all the selected greenhouse shapes. The mathematical model of the greenhouse global solar radiation is applicable not only to different regions of the world but also to other types of buildings. This analysis compared six typical greenhouse shapes commonly found in southern China (even span, uneven span, ellipse, arch, sawtooth, and vinery) to select the most suitable type for maximum solar radiation capture. The latitudes ranged from 20 degrees N to 30.6 degrees N. In addition, we considered the orientation of the greenhouse and calculated the cost savings per square meter regarding greenhouse heating in winter. The results showed that sawtooth captured the highest amount of global solar radiation in winter at all latitudes. E-W orientation greenhouses captured the maximum amount of global solar radiation in winter at all latitudes.