When there is an angle between the anisotropic metamaterials' optical axis and the electromagneticwave propagation axis, anomalous omnidirectional total reflection and anomalous negative refraction are discovered at the interface. The functional relation between incident angle and refractive angle of energy flow is obtained. According to this relation, we can restructure the refractive angle as negative or positive readily by selecting suitable permittivity and permeability tensors. And under these conditions, an anomalous transmittance emerges，such that when incident angle is less than a value, especially in the vicinity of vertical incident, the transmittance is minimum or even zero. According to these characteristics, a new slab spatial filter is put forward. Compared with the traditional space filter system, this new spatial filter's volume is smaller. And these characteristics can also be used to build a reflector of low spatial frequency.