To accurately analyze the shrinkage and creep effects in external prestressed reinforced concrete beams, a method was proposed for analyzing the shrinkage and creep of such beams based on refined finite element analysis. First, considering the force characteristics of the external prestressed tendons as constant-strain components, a differential treatment was performed on the geometric and nodal displacement relationships between the external prestressed tendons at the anchorage and deviation points and the concrete beam. Using the principle of virtual work, the element stiffness matrix that needed to be iteratively solved was derived for the external prestressed tendons. Second, based on the assumption that there was good bond between the reinforcement and the surrounding concrete under the action of shrinkage and creep, and that both materials exhibited coordinated strains, a finite element model was established for analyzing the shrinkage and creep of reinforced concrete beams that incorporated the effects of the reinforcements, utilizing the initial strain method in shrinkage and creep analysis. Finally, based on the aforementioned results, a method for analyzing shrinkage and creep in external prestressed reinforced concrete beams was established, along with the development of the corresponding programs. An analysis of the shrinkage and creep of two external prestressed reinforced concrete beams was conducted, and the results were compared with relevant literature. The findings indicate that the method established in this paper for analyzing the shrinkage and creep of external prestressed concrete beams is accurate. It was observed that in the computational model, treating the external prestressed tendons as if they were bonded internal tendons, or neglecting the influence of ordinary steel reinforcement in the concrete beam, can lead to significant errors in the calculated results.