Abstract: The Fluent module in CFD software was used to conduct a numerical simulation study on the flow field effects of the isosceles triangular artificial reef unit. The artificial fish reef parameters C (inclination angle A, opening ratio e, and flow-facing angle) were set, and the upwelling and back vortex flow field effects under four flow velocities (0.4 m/s, 0.6 m/s, 0.8 m/s, 1.0 m/s) with C=(20°, 0.2, 0°) were compared. Additionally, the upwelling and back vortex flow field effects under combinations of four e values (0.2, 0.3, 0.4, 0.5) and four A values (0°, 10°, 15°, 20°) were analyzed. Furthermore, the upwelling and back vortex flow field effects of the optimal model C=(20°, 0.2, θ) that is with a better combination of inclination angle and opening ratio, under four flow-facing angles (0°, 15°, 30°, 45°) were compared. The results indicated that: (1) When the flow velocity was 1.0 m/s, the reef body placed perpendicular to the incoming flow generated a significant upwelling and back vortex in the flow field; (2) When θ=0°, in this simulation working condition, the best inclination angle and opening ratio of the reef, A=20°, e=0.2; (3) C=(20°, 0.2, 0°) the flow-facing angles of the reef at θ=0° has the maximum value of about 1618 cm³ and 61590 cm³ respectively, with better material exchange capacity, fish gathering effect and good economic benefits.