In order to reduce the size of adapter, ensure the output synchronization of detonation wave and increase the connection strength between adapter and detonation fuses, a new way of splitting detonation fuses was put forward, and a small adapter with Φ5 mm×6 mm was designed.The prototypes of "one input two output" and "one input four output" flexible linear explosive circuit were manufactured, tested and analyzed. The results show that this small adapter can work reliably, and the output deviation of "one input two output" and "one input four output" flexible linear explosive circuit are less than 34 ns and 73 ns, respectively. Moreover, the interface between booster charge and detonation fuse in the adapter is found to affect the output synchronization of detonation wave.