Zr_1-xCoNb_x (x = 0, 0.05, 0.1, 0.15, 0.2) alloys were prepared via vacuum arc-melting method. The effects of substituting Zr with Nb on the structure, hydrogen absorb/desorb properties and anti-disproportionation performance of the afore-mentioned alloys were systematically investigated. The results showed that Zr_1-xCoNb_x (x = 0-0.2) alloys exhibited ZrCo and ZrCo₂ phases, and their corresponding hydrides consisted of ZrCoH₃ and ZrCo₂ phase. As the Nb content was increased, the activation time decreased significantly from 6790 s for ZrCo to 380 s for Zr_0.8CoNb_0.2. The activation energy for hydrogenation decreased from 44.88 kJ mol^_-1 H₂ for ZrCo to 32.73 kJ mol^_-1 H₂ for Zr_0.8CoNb_0.2 alloy. DSC measurement results showed that the desorption temperature decreased from 597.15 K for ZrCo to 541.36 K for Zr_0.8CoNb_0.2 and the activation energy for dehydrogenation decreased from 100.55 kJ mol^_-1 H₂ for ZrCo to 84.58 kJ mol^_-1 H₂ for Zr_0.8CoNb_0.2 alloy, which was beneficial to the anti-disproportionation properties. Additionally, the extents of disproportionation of alloys after disproportionated at 798 K for 10 h decreased from 83.68% for ZrCo to 8.71% for Zr_0.8CoNb_0.2. The positive effect of Nb substitution on improving the anti-disproportionation propertis of ZrCo alloys was attributed to the reduction of hydrogen atoms in 8f₂ and 8e sites, which decreases the driving force of the disproportionation reaction.