In this paper, the design, construction, simulation, and performance of a position-sensitive plastic scintillator detector are presented. The readout of the detector uses wavelength-shifting fibers coupled with multi-anode photomultipliers (PMTs) for the x- and y-dimensions. After calibrating the multi-anode PMTs, a two-dimensional projection image of the square scintillator telescope hit by cosmic muons is demonstrated. By performing a cosmic test with the Micromegas telescope, the position resolution of the detector was determined to reach approximately 8.6 mm, which is close to the value obtained in physical simulation.