Abstract: Based on the case of Lanzhou sprinkler pollution control policy,the problem of policy change is studied creatively by using clear set qualitative comparative analysis method. The analysis shows that top-down political variables,public opinion pressure,media pressure,expert pressure,and leadership change can be used as the driving factors of the policy change. Central media pressure is a necessary condition for policy change. According to the combination of different drivers,Lanzhou sprinkler pollution control policy changes have four evolution paths, of which the shortest path is "central media pressure and network media pressure" and "leadership instructions and central media pressure." In addition,in this policy case, the leadership not only cannot lead to policy changes, and even does not constitute a necessary condition for change. Whether it is "local leadership message board" or "portal message board" are non-policy changes in the full or necessary conditions, the public did not have the right to construct, the public did not become the main body of the construction, relying solely on the construction of interactive platform is not able to change the original policy construction order,and therefore can not Promote policy changes to highlight public opinion.