In order to reduce the construction cost of a compound multi-surface concentrator and improve its utilization efficiency of solar energy, the single-layer glass tube embedded absorber is selected as the photothermal conversion component of a compound multi-surface concentrator. The influence mechanism of the absorbers with different shapes in the single-layer glass tube on the photothermal performance of a compound multi-surface concentrator is mainly studied. First, the optical model of the concentrator is established in the optical simulation software TracePro, and the influence mechanism of absorber shapes on the optical performance of the concentrator is simulated and analyzed based on the Monte Carlo algorithm. Then, the influence of absorber shapes on the outlet temperature, instantaneous heating collection and photothermal conversion efficiency of the concentrator are analyzed. The results show that under the same incident angle, the number of light received by the “*”-shaped absorber is more than that received by the rectangular mesh receiver. When the incident angle is in the range of 0°--20°, the average light receiving rate and the average concentrating efficiency of the concentrator embedded with the“*”-shaped absorber are 7.37% and 6.66% higher than that of concentrator embedded with the rectangular mesh receiver, respectively. Under sunny weather conditions, the average outlet temperature, average discrepancy between air temperature of inlet and outlet, average instantaneous heating collection and average photothermal conversion efficiency of the concentrator embedded with “*”-shaped receiver are 48.5 ℃, 23.2 ℃, 467.5 W and 54.85%, respectively, which are 43.07%, 31.82%, 29.83% and 24.52% higher than that of the rectangular mesh receiver, respectively.