abstract:The inner 500 pc of our Galaxy contains a large amount of dense molecular gas, known as the Central Molecular Zone (CMZ). However, its star formation is observed to be about 10 time less efficient as compared with the prediction from the dense gas star formation relations that are well established toward nearby clouds and external galaxies. This challenges our current understanding of star formation, and may be the key to addressing the variations of star formation efficiencies in external galaxies. The question can be treated as a 'reverse problem' of the canonical star formation model, i.e., by knowing how star formation takes place, we investigate whether any step in this procedure is disrupted. Under this framework, I will suggest a few possible directions of exploration to decipher the inefficient star formation in the CMZ, and introduce our recent work based on latest interferometer observations including ALMA, JVLA, and SMA.