The time-delayed generalized projective synchronization problem for a class of piecewise modified Lorenz-Stenflo chaotic system with unknown parameters is discussed. The adaptive nonlinear feedback controller and the parameter update rules are designed based on the Lyapunov stability theory, and the feedback gain can be adjusted adaptively according to the error values and the states. The method can make all full states asymptotically generalized projected synchronization and identify the real-time drive system and the time-delayed response system’s unknown parameters. Results of simulation verified the realistic feasibility and effectiveness of the proposed method to the time-delayed generalized projective synchronization of the piecewise chaotic system.