In this paper, a micro-watt multi-port register file with wide operating voltage range for micro-power applications is presented. Multibank architecture for simultaneous access with collision detecting technique is proposed. The architecture has been analyzed under wide operating voltage range between 1V to 0.25V with varies process corner. Negative voltage write scheme ensures successful write in deep sub-threshold region. Also, an improved read buffer footer and controllable pre-charge in read scheme are designed. A 4W/4R 16KB register file is implemented in UMC 90nm CMOS technology. The simulation results show that the maximum active power of multi-port register file can achieve near 22.3-22.9uW at 485 KHz under 0.25V.