Aerated Concrete has been being studied and applied in Vietnam since 1980s, however, this material has been strongly invested to manufacture since 2010 oriented by Vietnamese concessional policies. Up to now, the manufacture of aerated concrete still shows many limitations, especially for Non-Autoclaved Aerated Concrete (NAAC). In fact, there is no official document for guiding NAAC mix design in Vietnam, and this causes one of difficulties for developing and applying this concrete. This paper proposes one method for NAAC mix design using fly ash and superplasticizer. Some factors on properties of NAAC, i.e. the water to solid ratio, the C index (silk to binder ratio), and the amount of aerated agent were also evaluated in this research. The NAAC with dry density of 700-800 kg/m) and compressive strength of over 5.0 MPa is one sample calculated following this proposed method is introduced and further verified by experimental studies in this paper.