A theoretical study is presented on spin-dependent electronic properties in reconstructed zigzag edge of silicene nanoribbons in the presence of external electric and magnetic fields and the intrinsic spin-orbit interaction . The effect of various models of edge disorder, such as the extended Klein and 5-7 and 5-8 reconstructions, on electronic structure was investigated. We showed that in the presence of external electric and magnetic fields, all reconstructed edge states may be manipulated to produce a half-metallicity and a fully spin-polarized current at the Fermi energy. Moreover, we found a general condition to produce a half-metallicity in reconstructed silicene nanoribbons. The results show that in the case of the extended Klein reconstruction, the half-metallicity can be found when, i.e., and , but in the case of 5-7 and 5-8 edges, the half-metallicity is reached when and , respectively.