Abstract: The relationship between the quality gaps and the knowledge gaps in a new product development process is researched, and the mathematical models for the quality gaps and the knowledge gaps are constructed respectively. In a new product development process, the knowledge gaps are the main source of the quality gaps. The total quality gaps and the corresponding total knowledge gaps are respectively formed by an accumulation of the quality gaps and the knowledge gaps produced in the phases of the development process. The quality gaps nonlinearly increase with the development process, and the quality gaps produced in initial phases contribute more to the total quality gaps. In a knowledge process cycle, the knowledge gaps nonlinearly increase with the knowledge process, and the knowledge gaps produced in initial phases contribute more to the total knowledge gaps. The total knowledge gaps in a new product development process equal to the summation of the knowledge gaps produced from each knowledge process cycle.