The development of low cost, earth-abundant and efficient catalysts for overall water splitting, involving hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), attracts tremendous attention in recent years. Herein, this work reports the preparation of Mn-Co phosphide (Mn-Co-P) bifunctional catalysts with a yolk-shell structure by a facile hydrothermal route. The as-prepared catalysts exhibit excellent catalytic activity with low overpotentials of 66 mV at 10 mA cm-2 for HER and 355 mV at 50 mA cm-2 for OER in 1 M KOH, along with outstanding stability. More importantly, the cell voltage of 1.74 V can achieve the current density of 10 mA cm-2 when assembled as an electrolyzer for overall water splitting. Such superior performance makes the Mn-Co-P being a promising candidate to replace Pt-based noble metal catalysts for electrocatalytic applications.