Estimating cylinder wall temperature before start of fuel injection in a dynamic and cycle-by-cycle way is important for advanced combustion mode engine control, particularly during cold-start and transient operations. In this paper, two methods for cylinder wall temperature estimation, based on disturbance observer designs, are proposed. The heat transfer through cylinder wall is viewed as a disturbance in total heat release. With disturbance observers, this heat transfer can be estimated in finite time and thus to calculate the cylinder wall temperature. To handle the high frequency noise issues in cylinder pressure signals, a robust disturbance observer is proposed and compared with a typical design method. The effectiveness of such cylinder wall temperature estimation methods are demonstrated and compared with engine experimental data obtained during a cold-start process.