Abstract: Four factors, weather condition, traffic in the area, waterway conditions and the performance of the large container ship, are identified as 4 influencing factors of the risk which piloting at Yangshan port. The qualitative and quantitative methods are jointly used to perform the risk analysis. The qualitative analysis indicates that the complicity of the traffic flow in Yangshan port area is the most important factor influencing the navigation mode（being piloted or Navigating by itself with aides） of the container ships. And the quantitative analysis further reveal that the influence is moderate for 49% of the ships and significant for 30% of them. The economic model for piloting in heavy weather in the area is built to estimate the direct and indirect economic benefits of the business. The analysis shows that a single voyage can bring in about 254 919 dollars.