The invention relates to a stay cable type sealed net structure. Newly-built iron towers are arranged at two sides of a spanned object of a cross spanning site, a sealed net is connected between support beams which are fixedly arranged at middle parts of the newly-built iron towers at the two sides, the sealed net is arranged above the spanned object, net pulling ropes at two sides of the sealed net respectively penetrate through the support beams of the newly-built iron towers and are fixed on the ground by ground anchors, and the stay cable type sealed net structure is characterized in that a stay cable is connected between the sealed net and top ends of the newly-built iron towers at the two sides. A stay cable type sealed net construction tool of a stay cable type sealed net device is mainly concentrated on the newly-built iron towers, the situation that a traditional U-shaped sealed net construction tool is fixed on a sliding rope or a net pulling rope is reduced, the construction preparation and the tool application are reduced, and the problem that a wire or a traction rope can deviate from a protection net and falls off on the spanned object on the condition of windy weather or blocking of the spanned object to break a line is solved. Although the support rack is simple in structure, the technical problem occurring in U-shaped sealed net construction is effectively solved.