Abstract: The original supporting design of the south side of this foundation pit is earthnail retaining wall.During construction of the earthnail retaining wall a poor drainage was caused by continuous rainfall,rain water entered back the earthnail retaining wall through the underground drains near the foundation pit's southern slope,together with non-standard construction methods,hence large areas of collapse have occurred in quite a few earthnail retaining wall and slope under construction.It was carried out a detailed analysis of the project incidents.After determining the cause of the accident,it was adjusted the original design scheme i.e.the scheme of anchor and brick wall composite structure was used.And a few of advice is provided for the construction of the earthnail retaining wall in loess region,such as attention to drainage,standard and informational construction,dynamic design.