The main causes of stability scaffolding loss with the drilling and blasting method construction in the roadway of the working face based on the mechanics was analyzed, and based on this, trellis chain fall preventing device was developed. The application or this device in 13190 working face indicated that this device had the advantages of simple installation, easy operation, convenient movement, low cost, greatly reduced the time and labor when upping the shed, greatly improved the roadway excavation rate, with significant economic and social efficiency, and indicated that this device had good popularization significance.