This paper presents a method of piston stroke design optimization for linear compressor to get high efficiency.Two linear compressor prototypes were designed and developed with the same discharge volumes and different piston strokes to compare the performance. The prototypes were operated without air load to measure the friction damping coefficient firstly. Then the prototypes were operated with air load of 0.7MPa discharge pressure. The experimental result shows that the input power of the prototype with longer stroke is lower than that of the prototype with shorter stroke although the discharge volume, the friction damping coefficient and the frequency ratio of these two prototyps are almost the same. The iron and coil loss of the prototype with longer stroke is lower than that with shorter stroke, while the mechanical loss of the prototype with longer stroke is larger than that with shorter stroke. According to the results of the performance analysis, a design optimization model for piston stroke is developed to make the energy loss be the least. Through this design optimization model, acquire the optimal piston stoke of the linear compressor on the same conditions with the experiment. The optimization results agree well with the experimental results.