Abstract: The effect of spanwise-arranged inclined minute jets on the turbulent flat-plate boundary layer is investigated numerically, and it is confirmed that such minute jets can produce streamwise vortices to control boundary layer. The influences of jet primary parameters on the control action are analyzed. When the skew directions of jets are one, the control action of streamwise vortices weakens one by one along the skew direction; while the skew directions of neighbor jets are contrary, the control action is more uniform in a larger streamwise extent. With the jet spacing decreasing, the initial control action of streamwise vortices improves, but the control action fades more quickly downstream. Under lesser jet velocity, higher jet velocity brings better control action of streamwise vortices; while excessively high jet velocity leads poor control action instead due to streamwise vortices penetrating through boundary layer. Lower jet pitching angle (generally less than 30) and higher jet skew angle (generally larger than 60) are helpful to the control action of streamwise vortices.