To enrich the electronic and induce useful magnetic properties of the monolayer black phosphorene (BP) we study the structural, electric and magnetic properties of substitutional 4d transition metal (TM) impurities in BP by means of first-principles methods. In the 4d single TM atom doped cases, the magnetic moment shows oscillation character with the increasing of the 4d shell valence electrons, which is attributed to the P-p and TM-d orbital hybridization mechanism. We found no spin polarized state in the Y, Nb, Tc, Rh and Cd doped BP. In other systems, the spin polarized states are found. Importantly, the 4d TMs also enrich the electronic properties of BP, such as half-metallic, metallic and semiconducting features. For two same TMs doped BP, the 2Mo doping on the both sides of BP show a half-metal character. Only 2Nb doped BP shows diluted magnetic semiconductor (DMS) character. Interestingly, for two different TMs doped BP, the DMS characteristics can be found in the MoY-BP, MoNb-BP, MoTc-BP and MoRh-BP cases. It is worth to be expected that doping with different 4d TMs is a promising method to realize the DMS properties of BP.