The present invention relates to a pyrimido[5,4-b]indolizine or pyrimido[5,4-b]pyrrolizine compound, a preparation method and a use thereof. The compound of the present invention has good inhibitory activity on BTK both at the molecular level and the cellular level. Importantly, the compound of the present invention has relatively low activity on the common human B lymphoma cell Ramos cell, and has high activity on the BTK-sensitive human diffuse large B lymphoma TMD8 cell, which suggests that this structural type of compound has a very relative selectivity, and has a relatively low off-target and corresponding side effect, and is a BTK-selective inhibitor having a development potential.
