To address the challenge of effectively controlling high dust concentrations during drill-and-blast tunnel construction, a curtain-type spray dust suppression device is developed, and its atomization performance and dust suppression effectiveness are comprehensively evaluated. Based on the characteristics of the tunnel construction environment, a device consisting of multiple annular spray pipelines is designed and fabricated, forming a vertical mist curtain behind the tunnel face to block longitudinal dust dispersion. A computational fluid dynamics model of dust diffusion under typical construction procedures is established using data from the Zijingyaoshan tunnel, and the effects of different ventilation conditions, spray pressures, and layout parameters on dust diffusion are systematically analyzed through simulation. Field tests are also conducted to obtain the spatiotemporal distribution of total and respirable dust concentrations. The results show that the curtain-type spray dust suppression device effectively interrupts longitudinal dust transport and significantly reduces dust concentration in tunnels. At a distance 30－60 m from the tunnel face, the average suppression efficiency of both total and respirable dust exceeds 80%; in the area directly beneath the device (40 m from the tunnel face) and in downstream sections (50 and 60 m from the tunnel face), the efficiency exceeds 90%. These findings indicate that the device is highly effective in suppressing dust particle dispersion and reducing dust concentration in tunnels. With its simple structure, flexible layout, and strong adaptability, the device provides valuable reference for promoting and applying dust suppression technologies in tunnel construction.