To detect cleavage activity of anti HBV two unit ribozyme and single ribozyme,and compare two conected ribozyme cleavage efficiency with two mixed ribozymes, firstly, Rz1,Rz3 and Rz13 ribozymes transcription vectors were constructed,then cleavage activity of Rz1,Rz3 and Rz13 ribozymes on target RNA were observed. The results showed that antiviral activity of two unit ribozyme,whether connected (Rz13)or two mixed ribozymes, has higher cleavage efficiency than single ribozyme. Cleavage efficiency has no difference between connected (Rz13) and two mixed ribozymes( n =2, P 0 05).