To study the temperature field and temperature effects of a continuous rigid-frame bridge with horizontal bottom cables, a large-span prestressed concrete continuous rigid-frame bridge with a horizontally arranged bottom cable system was selected as the research object. A Python program was developed to calculate the solar radiation boundary conditions, and the Abaqus software was used to establish a two-dimensional transient heat conduction model of the bridge. The time-dependent temperature field of the bridge during summer and winter was analyzed. Based on this, the temperature effects caused by the vertical temperature gradient, transverse temperature gradient, effective temperature, and various temperature modes on the bridge structure were further investigated. The research results show that the temperature distribution characteristics of the bridge cross-section calculated by the finite element method are in good agreement with the current specifications. The horizontal arrangement of bottom cables can effectively improve the mechanical performance of the continuous rigid-frame bridge and reduce the temperature effects during the operational period.