In order to improve engine performance and reliability, it is important to measure the friction force between the piston-ring assembly and cylinder wall, and to understand the friction characteristics. A new device was developed in this study for piston friction force measurement. Compared with existing floating liner systems this device requires less installation space and alleviated the system noise problem induced by piston thrust and slap impulse forces. This system was used for friction force measurement to determine the functional relationship between friction force and variables such as engine speed, oil viscosity and engine load. The friction force characteristics were established from the analysis of the experimental data.