To study the effect of reducing the core area of the stator on the iron loss in the fractional slot concentrated winding (FSCW) permanent magnet (PM) synchronous machine, two sets of research schemes are proposed for the stator slots, which are based on the 8-pole/9-slot PM machine, including only increase integer multiple of the stator slot width and the number of stator slots without changing the stator slot size by finite element analysis (FEA). Then, the principle of iron loss calculation and detailed comparisons of the performance characteristics of the machines are presented that include important issues such as the harmonic of Back EMF, stator yoke flux density, iron loss and eddy current losses in the magnets. With this result, an optimization is carried out to determine the width of stator slot, which reduce the iron loss, magnet eddy current loss and harmonic content without significant decreases in the performance. It is found that properly increasing the width of the stator slot to reduce the influence of iron loss is better than increasing the number of stator slots of the machine. In addition, the torque ripple is affected by the number of slots, it has nothing to do with the area of each slot when the number of stator slots is constant.