In order to solve problem of measuring the inner surface roughness and realize the full surface roughness measurement, a white light confocal method for measuring the full surface roughness is proposed. Based on the white light confocal sensor, the measurement system is built, and the workpiece clamping structure, the measured surface positioning structure, the sensor focusing structure and other structure are designed. The software system is developed on the C# platform, and the full surface roughness measurement ability is estabished. Verification experiments have been carried out on the standard multi-scribed template and curved surface samples. The experimental results show that the measuerment system has high indication accuracy, repeatability and stability, and has the ability to measure the full surface roughness of curved surface parts.