In order to investigate the effect of cutting speed on chip morphology and machined surface topography of a new type free-〖JP〗cutting steel,the cutting experiments of a new type free-cutting steel were carried out at different cutting speeds,the chip morphology and machined surface topography were studied and the causes were analyzed.The results show that the free-cutting steel chip shape is mainly short tube spiral when the cutting speed is greater than 150 m/min,the free-cutting steel chip shape is mainly strip and broken arc when the cutting speed is less than 150 m/min,the critical cutting speed for saw-tooth chip formation is approximately 200 m/min;cutting speed has a great influence on the morphology on chip bottom,there will be more tearing pits and grooves with different sizes on the bottom of the chip when the cutting speed is low,however,when the cutting speed is increased to more than 200 m/min,a smoother chip bottom surface can be formed;the machined workpiece surface roughness values are larger,and the 3D morphology of machined workpiece shows that the peak height and trough depth are also large when the cutting speed is low,the workpiece surface roughness decreases with the increase of cutting speed,the 3D topography of the machined surface tends to flat with the increasing of cutting speed.