Human error is the main factor in the collapse of scaffolding. The characteristics of such human errors and divides them into structural errors and parametric errors was analyzed. The calculation method and calculation method of initial human error incidence based on field survey data are given. Probabilistic model of error size, an improved evidence fusion method is proposed, an interval model of error retention rate and its calculation formula are given, and a mathematical model of human error in fastener-type scaffolding is established. Based on the above mathematical model, an interval analysis method of human factor reliability is given, which provides a theoretical basis for studying the safety of scaffolding.