To reduce forward vortex losses caused by discontinuous curvature in conventional polyline Tesla valves, this study introduces Bezier curves into Tesla valve design to improve unidirectional flow control through curvature continuity. Eight differentiated Bezier-curve configurations (ta-th) are designed, covering concave, convex, and baseline combinations of Curve 1 (inlet to bifurcation midsection) and Curve 2 (bifurcation midsection to outlet). The channel section is set to 3 mm × 2 mm with a bifurcation angle of 20°. A CFD model is established using the standard k-ω turbulence model, with a velocity inlet of 5 m/s and a pressure outlet of 0 Pa gauge to analyze forward and reverse pressure drops, diodicity, and the distributions (pressure, velocity, and turbulent kinetic energy). The results show that the tc structure (concave Curve 1 and convex Curve 2) achieves the best unidirectional flow performance, with a diodicity of 1.700183, a reverse pressure drop of 16035.53 Pa, and a forward pressure drop within 9400–9700 Pa. A concave Curve 1 improves forward flow uniformity and reduces energy loss, whereas a convex Curve 2 strengthens the contraction-expansion effect in reverse flow and enhances blocking capacity. This study confirms that Bezier curves address the structural deficiencies of conventional Tesla valves, establishing links among quantitative geometry, flow, and performance and parametric design rules. This fills a research gap in continuous-curvature structures and provides high-performance passive fluid control for EV thermal management, flame safety, wastewater treatment, as well as theoretical guidance for other passive fluidic devices.