An advanced tangential X-ray pinhole camera (TXPC) has been developed for KSTAR by utilizing a 2-D duplex multi-wire proportional counter (MWPC) detector. The KSTAR MWPC employs a 2-D parallel type readout system for high temporal resolution and adopts a duplex type for the capability of electron temperature measurement via the multi-color method. This paper presents the performance test result of the developed MWPC system utilizing a Fe-55 X-ray source. As a preliminary experimental result from the 2012 KSTAR campaign, the clear presentation of sawtooth activities and its frequency change, and 2-D plasma images during the vertical disruption event are given. (C) 2013 Elsevier B. V. All rights reserved.