Hydrogenation of nitrile butadiene rubber (NBR) latex is an important topic in the field of chemical modification of unsaturated diene-based polymers. At present, the main challenge that restricts the large-scale production of hydrogenated nitrile rubber (HNBR) via latex hydrogenation way is how to reduce or even eliminate the use of organic solvents and to achieve a high rate of hydrogenation combined with a low amount of catalyst. We found a high-efficiency catalyst, i.e., catMETium®RF 4, which can directly hydrogenate NBR latex. The effects of temperature, hydrogen pressure, concentration of [CC]₀ and agitation speed on the rate of hydrogenation were fully investigated. It was found that by using catMETium®RF 4 catalyst to prepare HNBR, the rate of hydrogenation of NBR latex can be increased drastically to achieve a high CC conversion of 95 mol% with a very low catalyst level of 0.02 wt%, which greatly decrease the demand on the recovery of a homogeneous catalyst from HNBR matrix. In addition, the hydrogenation of HNBR latex by catMETium®RF 4 was completely free of organic solvents and no cross-linking was found.