In this paper, a double-layer tube trough solar cascade heat collection system (enhanced PTR) with fins is proposed, and a numerical model is established to study its flow, heat transfer and heat collection performance. Under the condition of a certain fin volume, the influence of the structural parameters of the fins on the enhanced PTR performance is studied. The results show that, compared with the traditional PTR, the temperature of the outer wall of the absorption tube and the outward heat flux of the enhanced PTR are significantly reduced on the entire circumference. Within the range of fin structure parameters studied in this paper, the heat transfer performance and flow resistance of enhanced PTR are increased to 1.83∼3.45 and 3.99∼7.25 times of smooth tube and the comprehensive heat transfer performance is 1.16∼1.78.The heat loss of enhanced PTR decreases by 42.4%∼47.8%, pump power consumption increased by 331%∼691%, heat collection efficiency increased by 1.71%∼1.93%.The range of heat collection efficiencies of hightemperature/low-temperature fluid are respectively 55.12%∼55.69% and 15.31%∼15.69%.