Light beam attenuator is one kind of optical element which has been widely used in optical technique. According to beam attenuation principle, it can be divided into two kinds, one is absorbing type attenuator, the other is non-absorbing type attenuator. There has been considerable attention paid to study visible attenuator, but there are few ways to attenuate 3.39 micrometer laser beam. In this article we have introduced a series new type 3.39 micrometer laser beam attenuator made by using birefringent crystal. Some is absorbing type attenuator, the other is non-absorbing type attenuator. Such as: two calcite parallel plates type, two yttrium orthovanadate prism type, two yttrium orthovanadate parallel plates plus lambda/2 waveplate type, etc.