Abstract: Operation quality test methods of loosening and perturbation coefficient of soil for deep loosening machine were researched.Surface mapping and calculation of cross section area were optimized.Contrastive test between instrument measurement method based on laser range finder and traditional manual measurement method was carried out.Results showed that there was no significant difference between instrument measurement and manual measurement.It was proved that the improved method was accurate and reliable.And it could be applied to both instrument measurement and manual measurement.The advantages of instrument measurement was to avoid influence of human factors on the results and collect data furthest.So it could improve test efficiency，convenience of data processing and accuracy of measurement results.