Abstract: In order to reduce the turbulent frictional drag of high-speed aircraft, trains and other transportation vehicles, this paper experimentally investigated the effect of microjet array parameters on the drag reduction effect and net energy saving of constant blowing in a turbulent boundary layer with high Reynolds number. The experiments were carried out in a reflux wind tunnel, based on a flat plate exciter with 0.3 mm slit width and 3 mm plate thickness, designed and tested with different porosities (5%-15%) and slit tilt angles (0°, 30°, 45°, 60°), and the wall friction resistance was measured by using a high-precision air-floating force balance. The experimental conditions were based on a friction Reynolds number of 3340 < Re_\tau < 5480, corresponding to a momentum Reynolds number of 8674 < Re_\theta < 15102. The results showed that the slit structure itself introduces surface drag enhancement, and the amount of drag enhancement increases with Reynolds number. Constant blowing significantly reduces the wall friction resistance, and the drag reduction mainly depends on the blowing intensity, with the maximum drag reduction rate reaching more than 70%. The slit angle had a significant influence on the drag reduction effect, and the drag reduction effect of the spreading slit (0°) was better than that of the inclined slit. The optimal net energy saving rate of 16.11% was obtained at Re_\tau = 5480 for the flat blowing plate with spreading slit, corresponding to an optimal blowing intensity of 0.00375.It was also found that the optimal net energy saving rate increased with the increase of Reynolds number. This study reveals the key role of microjet array angle in blowing drag reduction and energy saving, and provides experimental basis and optimization direction for the engineering application of active flow control technology.