Porous self-lubricating PEEK composites (PSPC) with nano-micro multilevel pore structure (N-MPS) incorporated by ionic liquid were fabricated via molding-leaching and vacuum suction technologies. The tribological properties of PSPC with different porosities were investigated using a tribotester under an applied load of 250 N and a sliding speed of 0.69 m s(-1). Moreover, a finite element (FE) model with N-MPS was firstly developed to reveal the nano-micron scale collaborative lubrication mechanism of the composites. The temperature field, von Mises stress, and displacement fields of the FE model under different porosity conditions were studied in heat-stress coupled field using ANSYS software. The accuracy of the simulation results was verified by comparing them with corresponding experimental results with the error values < 10 %. Both the experiment and simulation results showed that the PSPC exhibited excellent tribological properties when the porosity was 16.8 %. It reflects that FE method is capable of studying the self-lubricating process of nano-micro multilevel porous composites with an optimized FE model.