Burning rate is a determinate Parameter in Performance Prediction of Solid Propellant motors. Any error in determining the burning rate directly affects the prediction of thrust and burning time. Small-scale rocket motors are widely used by space and military industries to carry out burning rate measurement. The use of Subscale motors has many advantages over more simplistic, such as strand burners. Effects like: Two phase flow, radiation, and erosive burning effects are present within a subscale test whereas strand burns are not capable of capturing these parameters. The biggest problem with subscale burning rate motors however is determining appropriate times for when the propellant grain has lit and burned out. Accurate and consistent selection of start and end points is crucial to determining the burning rate of a given propellant. Investigation of Developed and modern methods to obtain burning rate from motor test according to the primary methods in Iran's aerospace industries is the main objective of this study. In this study, using designed laboratory solid rocket motor, 26 tests was Performed. Reproducibility of the methods available in universities and defense companies worldwide has been considered and with Common Tangent bisection method has been compared. Results show the high quality of industrial Methods subset the Thickness-time Method, Hessler-Glick, and mass balance method with comparing to low reproducibility of tangent bisection method