As the next generation of CNC standard, STEP-NC can be used to solve the current problem of information integration in digital manufacturing. With the characteristic of the STEP-NC data structure, the key technologies to approach the process planning by workingstep features based on STEP-NC are studied. Geometric information translating, feature information extraction, process planning, STEP-NC file generating are all involved. The detail of the lexical analysis of the AP203 files, the operating of the geometric information database and the translating from AP203 to geometric information database are studied. Applied the STEP-NC enabled technology, the system of process planning by features is established. The conclusion is useful for 3D process planning and the intelligent machining. The interoperable and integrated information between CAD/CAM is reached.