In this work, the microstructure and mechanical properties of as-cast Zr-14Nb (wt.％) binaryalloy was studied to develop a β type Zr alloy with excellent mechanical properties as structural biomaterialused under magnetic resonance imaging (MRI). Β and ω phase (very small amount) was characterized byX-ray diffraction and transmission electron microscopy (TEM) in Zr-14Nb alloy, and ω phase is diffusionin β phase matrix. Lenticular structures arranging in an almost parallel manner in each grain werediscovered by polarizing microscope (POM). The compositions of the structures are the same as other partsof the samples analyzed by electron probe microanalysis (EPMA). It is considered as a structure ofmartensites. Mechanical measurements revealed that Zr-14Nb alloy as cast showed outstandingcompressive mechanical properties, moderate tensile mechanical properties and low Young′s modulus.Fracture SEM images demonstrate well ductility of the alloy. Summing up the above, Zr-14Nb alloy haspotential applications in structural medical biomaterials.