Liquid crystal birefringent filter has advantages of room temperature operating,simple tuning,narrow bandwidth and better output characteristics.In order to design such filters with different tuning range and bandwidth to meet the needs of practical application,we make numerical simulation,select the device parameters and summarize the design ideas.We designed a narrow band transmission filter with output tuning range of 0.691~0.866 THz.The results show that through numerical simulation and analysis of key parameters that impact the tuning range and output bandwidth of the filters,design scheme can be set up for liquid crystal birefringent filter with different tuning range.The design example meets the expected requirements well.