Abstract: In view of problems that charger of Ni-MH batteries based on MAX713 is only used in charging for 1～16 Ni-MH batteries and exists virtual filling, the paper proposed a design scheme of intelligent charger of Ni-MH batteries which can charge for more than 16 Ni-MH batteries. The charger takes MAX713 as basis and uses serial way to link batteries, and is added timing detection function which can ensure fully filling of Ni-MH batteries through controlling relay by single-chip microcomputer. The actual application showed that the charger has certain practicability.