To meet the intrinsic requirement for nuclear weapons safety, the insensitive high explosive (IHE) was proposed by US military and 11 kinds of identification tests for IHEs and 5 kinds for IHE components were established further. However, with the development of HEs, the simplified classification of explosives into HE and IHE has limited the innovation of new explosives. Meanwhile, there are not strict definitions and assessment standards for low-sensitive, insensitive and sensitive explosives. In this article a more detailed classification with four classes for the main charges regarding the sensitivity is proposed. That is, the class A means insensitive and complies all the 11 requirements of IHE, e.g. LX-17, PBX-9502. The class B means they are quasi-insensitive and complie 9-10 the requirements of IHE, e.g. LLM-105 based PBX. The class C means low-sensitive, e.g. PBX-9501. And the class D means sensitive, e.g. PBX-9404. It is also proposed that the concepts of insensitive initiators, primary and booster explosives.