In view of the fact that shortage and uneven temporal and spatial distribution of rainfall in the semi-arid area of the Loess Plateau, this paper aimed to study the hydrothermal regime effect of the ridge-furrow planting mode, and reveal the mechanism of hydrothermal regulation and the enhancement of crop yield. Field experiments of open field treatment (CK) and plastic film combined with straw mulching treatment (RMFS) were conducted in 2014 and 2015 in Yangling, Shaanxi. The results showed that the plastic film combined with straw mulching cultivation had effects on the growth of summer maize, and the mulching could improve soil moisture condition. Soil temperature showed a phenomenon of ‘lowering the temperature when the temperature was high, and vice versa’. The RMFS treatment shortened the duration of crop growth and adjusted crop water consumption to improve the balance between water supply and demand. Soil water use efficiency and thermal time use efficiency was increased by 39.85% and 43.34% in the RMFS treatment in the second year, respectively. Although water consumption could not be saved and soil thermal time was not increased, soil water use efficiency and thermal time use efficiency were significantly improved. In short, ridge covered plastic mulching with furrow covered with straw mulching treatment improved crop yield by improving the hydrothermal interaction regime. Plastic film combined with straw mulching treatment is a suitable effective practice to collect rainwater harvesting.