Lately, nitrate glycerol ether cellulose (NGEC), a novel thermoplastic cellulose-based energetic binder, exhibits potential application to replace conventional nitrocellulose (NC) which was commonly used in propellants. This study employs NGEC as insensitive and reinforce materials to prepare NGEC-based energetic composites via a combined simple and safe water-suspension method and freeze-drying technology, involving NGEC/RDX (cyclotrimethylenetrinitramine), NGEC/HMX (cyclotetramethylenetetranitramine), and NGEC/CL-20 (hexanitrohexaazaisowurtzitan). The obtained composites have been systematically characterized and exhibited stable structure, improved thermal properties and reduced sensitivity (the largest is about 1.4 times) performances. These results demonstrate that energetic crystals and NGEC are combined tightly by van der weal force; and present favorable thermal stability, especially for the increased temperature of polymorphic phase transition with the increased content of NGEC (HMX (β→δ): 194.6°С→198.8°С, CL-20 (ε→γ): 164.6°С→177.9°С). Moreover, the existence of NGEC with different content has different influence on the decomposition performance of different explosives. Hence, this fabrication strategy of NGEC-based energetic composites may provide promising application in high-energy and high-strength propellants.