With the development of digitalized manufacturing (DM), on-machine inspection (OMI) has become the key link of integrated quality system in DM. In DM, The detection and monitoring system chiefly dealing with kinds of parameters in machining process, taking on-line detection, analyzing the process quality information and carrying out corresponding quality assurance, so the quality of product may be assured and DM can be run in good condition. Therefore, the OMI technology of machining center based is researched. The framework of OMI and the hardware structure of special driving card for probe or tool (SDCPT) are described. Computer aided inspection planning (CAIP) is the integration bridge between CAD/CAM and computer aided inspection. A feature-based CAIP system for OMI is proposed to inspect the complicated mechanical parts efficiently during machining or after machining. The CAIP system is designed to produce an inspection process planning directly from CAD model. The prototype CAIP system includes the tolerance feature analysis, accessibility analysis, feature identification, measurement planning, and collision detection. The CAIP system can minimize the number of part setups and probe orientations and the inspection feature sequence.