Matlab digital image technology is used to calculate the shrinkage ratio of carrot surface area. After studying the drying properties,the universal test machine is used to analyze the physical and mechanical characteristics of carrot slices to provide the basis for high speed shear smashing technology. The thickness of carrots slice,cutting method,moisture content,crushing amount and crushing time are designed as testing factors and the passing rate of 80 meshes sieve is the test indicator. With the help of Single factor test,orthogonal tests,range optimization,the stepwise regression mathematical model and optimization generated from the stepwise function in Matlab,the best technology parameters are confirmed as: radial cutting,3 mm's thickness,5% 's moisture content,smashing time3. 5 min,the carrot slices have the highest rate to go through 80 meshes sieve.