In order to research the effects of pretilt and twisted angles on the ne matic liquid crystal (LC) filter,based on the birefringence and distortion effects,the nematic LC filter has bee n analyzed through the deductive theory and simulated by MATLAB software.And its transmittance expression also ha s been derived from the optical theory. The further experiments indicate that the transmittance is associated with the pretilt angle and twisted angle.If the twisted angle is increased,the transmitta nce peak of the nematic liquid crystal filter will shift to long wavelength.With the increase of the pretilt angle,the liquid crystal filter transmission peak moves to the s hort wavelength and the peak′s shift rate is related to the wavelength-the sho rter the wavelength slower,the shift rate the pretilt angle of the bottom glass substrate is increased and that of the top glass substrate is reduc ed (or the pretilt angle of the bottom glass substrate is reduced and the top glass substrate is increased),the rate of tran smittance peak moving to shorter wavelength will weaken;and when the ratio of the incremental value of the pret ilt angle on the bottom glass substrate to the reductional value of the pretilt angle of the top glass substrate (or th e ratio of the reductional value of the pretilt angle on the bottom glass substrate to the incremental value of the pretilt ang le of the top glass substrate) is about 1.2,the center of the transmission peak will not drift.