In order to redesign and improve performance of EPU 4.6 for the Taiwan Light Source (TLS), implement new control system and develop application programs of EPU 4.6 are under way. The EPU 4.6 driver system includes 8 axes servo motors with Sin/Cos absolute encoder and 8 SSI absolute encoders for precision position control. Due to proprietary design of the vendor and lack of needed technical documents of the existed motor drivers and motor controllers, obsolete these devices and replaced by another open solution is the most difficult decision. A VME crate installs CPU board, DI, DO, AI and AO card, SSI read-only interface is used as EPU 4.6 controller. The motion controllers are connected to the VME CPU via Ethernet directly. The power supplies of correction coil are MCOR30 system manufactured by BiRa Systems. The simple PLC dedicated for interlock protection purpose which take input from limit switches, kill switches, tilt sensors and emergency button from the driver system. The interlock logic will restrict motion if any limit sensor is activated before removed and interlock reset. Features and benefits of the new control system of EPU 4.6 will be summary in this report.