Abstract: Analytical methods such as thermogravimetry-mass spectrum united technique, SEM morphology observation, phase analysis, pore size and specific surface area analysis, thermogravimetric analysis and static adsorption analysis were utilized to characterize 4A molecular sieve systematically, from which the properties from micro to macro were gained. Through the research, not only the comprehensive parameters of 4A molecular sieve were obtained, but also the important reference to reasonably set the service condition of 4A molecular sieve were introduced. In addition, the application of each characterization method was discussed, which could offer feasible ways to study other kinds of molecular sieves.