The “Double Reduction” policy exerts powerful leverage on the basic education reform in the new era, and plays a leading role in building a new pattern of basic education with more equity and higher quality. Using the Mazmanian-Sabatier policy implementation model in the field of public policy, this paper examines the various constraints in the implementation of the “Double Reduction” policy with the survey data of 30 counties (cities, districts) in 6 provinces. In terms of the tractability of the policy problem, there are various complex problems, different needs from the stakeholders and a wide range of behavior adjustment arising from the “Double Reduction” policy. In terms of the policy ability to structure the implementation process, there are the fragmentation and low mobility of the policy resources, the policy implementation constrained by the differences between urban and rural areas and school levels, and the insufficient “empowerment” of the implementation monitoring mechanism. In terms of the variables outside the policy affecting the implementation process, there are the long-standing test-oriented educational evaluation constraints and the influence of the negative Internet public opinions. Therefore, in order to relieve the constraints in policy implementation, the following suggestions are put forward: building a triple-space collaborative education ecology of family, school and society, improving the policy resources integration mechanism, implementing differentiated guidelines for policy implementation, improving the level of supervision of policy implementation, promoting the “attainment + value-added” evaluation reform, and optimizing the public opinion space of policy implementation.