Precise linearity method which is applied to linearize nonlinear chaotic system through strict state transform and feedback strategy is discussed. Considering that some of the state variables can not be measured, the nonlinear feedback method including state observer is researched, and the corresponding control law is deduced. This kind of control method is adopted to chaos synchronization control of the Lorenz system, the simulation results show that the synchronization error of the three state variables can convergence to zero in a short time, which indicates that the control procedure proposed in this paper can guarantee high convergence speed and precision of synchronization under the prerequisite of close-loop stability.