This paper suggests a flexible joint robot operated by brushed Direct Current (DC) motor model. Due to complex high-order, nonlinear dynamical system which operating under parameter's uncertainty, sliding mode control (SMC) used to solve this problem of control the flexible joint robot. The SMC method is identified as one of the effective method to design robust control for the flexible joint robot, which based on t using a Low Pass Filter (LPF) with suitable time constant. The mathematical model is presented clearly and the simulations together with their analysis are done using MATLAB software. Simulation results display the efficacy of the designed robust control in stabilizing the system states and forcing the link side angle to converge to the desired value with appropriate control effort.