The famous NOR-type flash memory structure is included to develop flash memory fault model in this work. The 13 realistic faults consisted of 11 functional faults and 2 parametric faults have been proven to likely occur if some undesired dust particles are dropped on the physical masks in natural manufacturing process. The proposed fault models will facilitate test engineers to put their test effort on effective and accurate fault models instead of utilizing classical "reduced functional fault models" to test flash memories. The classical fault model, which does not concern the physical operation and detail layout, may cost a lot of test time but fail to gain higher fault coverage. But such tragedies would not happen if the proposed fault model is adopted because the proposed one is based on the physical geometry of NOR-type flash memory, and verified by device simulator TMA/Medici.