Abstract: the aim is to research the method of tracing back to quality accident due to human-errors in assembly line for Intermittent Manufacturing.A method about hierarchical recognition of human-errors is developed by integrating the strongpoints both the Swain's classifying method and Rasmussen's S-R-K classifying method about human-errors.And based on this method the leak problems of sensor wiring harness due to human-errors in the assembly line is analysed by combining with the faults-tree analysis method.The research results state that the intrinsic factors(swiftnees,aleatory psychology,incaution) are the main reasons for human errors during assembly process of the sensor wiring harness.Otherwise,the influence of the circumstance and management factors on the leak problems of sensor wiring harness can not be neglected.