Aim: The main of this work is about Comparing machinability performance of Novel TiSiN coated HSS tool with uncoated HSS tool for CNC Green machining (CNC Turning) of high strength steel alloy (EN24) for improving machining rate and surface Finish. Materials and method: EN24 Steel rod of diameter 22mm and 50mm of length of rod is used in the research work, En24 steel was normalized at 800-860°C. Hold at this temperature then quench in oil .Test samples per (N=16+16=32) were CNC turning operation is used for find the surface finish and material removal rate taken from each rod of experimental group and control group.(Unalloyed EN24).Total sample size used for the Groups is 32 and 80% of G power is calculated using the software G Power 3.1. Result: Within this limitations of study the confidence level of cutting parameters and the response Surface Roughness values are obtained for all machined specimens with both HSS tool and Novel Titanium Silicon Nitride coated High speed steel tool and the results done by Turning were conducted with speed, feed and depth cuts to turning process with an MRR is 350mm3/min and depth of cut affects considerably cutting force and power (62.31% and 60.72%). And the Surface Roughness is 25.885%. Using TiSiN coated HSS tool gives lower surface roughness than HSS tool in Computerized Numerical Control machining.Surface roughness of samples, group wise statistically evaluated with SPSS software. T-test results show significance values are p=0.020<0.05 for Material Removal Rate (MRR) and p=0.033<0.05, for Surface roughness. Which reveals that the observations are statistically independent and observed statistical assumptions with no violation. The mean surface roughness for samples prepared with novel TiSiN coated HSS tool gives lesser surface roughness than HSS tool. Conclusion: Within the limits of study, the optimization of EN24 Material removal rate, Surface finish and Surface Roughness using response of Novel Titanium silicon Nitride Coated Tool. The results obtained revealed that spindle speed, feed rate and depth of cut have a significant influence on the MRR. The optimum machining setting of spindle at 500 rpm, the feed rate of 0.4mm/rev and depth is 0.2mm resulted in a turning process with an MRR.