Series three phase electronic type prepayment watt-hour meter is a kind of new-style meter which is developed by our company on the basis of type DDSY256 single phase electronic prepayment watt-hour meter and adopt micro-electronics techniques. It is used for measuring rated frequency 50Hz or 60Hz three phase AC active energy electric power consumption and realize using electric power after prepaying and perform load&control function for user. It is a kind of ideal product for reforming using electricity system and realizing electric energy commoditization and effectively control and adjust electricity net load. Its technique performance are completely conformed to National Standard GB/T17215-1998 and Department Standard JB/T8382-96.