Abstract: This study aims to satisfy the testing needs for the collection efficiency of filtration membranes used in ambient air sampling and to ensure the consistency and accuracy of these tests. It analyzes the key influencing factors and the feasibility of the filtration membrane collection efficiency testing methods. Subsequently, two testing schemes based on particle number concentration and particle mass concentration are developed to assess the collection efficiency of ambient air filtration membranes. This paper presents the principles, experimental device requirements, and procedures of these testing schemes. Tests were conducted on various materials and applications of ambient particulate matter sampling filters. The experimental results show a high degree of consistency between the two methods in terms of collection efficiency test conformity. However, the method based on number concentration yields slightly lower results compared to the mass concentration-based method. The differences are attributed to the inherent limitations of the testing methods and deviations caused by various detection devices, though these impacts are negligible overall. Both methods demonstrate high reliability and equivalence, laying a foundation for their use in practical applications. Depending on the configuration of their experimental devices, users can choose either method for testing the collection efficiency of filtration membranes, ensuring the test's accuracy and reliability.