German companies in the machine building and plant engineering industry as well as related industries develop Intelligent Technical Systems. These are sold worldwide, but they are threatened by imitation. There is a variety of possible attacks offered to the imitators to steal the system know-how and thereby manufacture illegal imitations. These threats need to be considered in the interdisciplinary system design. To ensure the effective system protection the design framework for the preventive protection of Intelligent Technical Systems from product piracy has been introduced, which covers this so far undervalued design aspect in the course of the development of Intelligent Technical Systems. This framework consists of four elements. The basis is built on protection requirements of Intelligent Technical Systems. On their basis protective measures are identified. To encounter the requirements of the system design, the description of protective measures is revised. Also a procedure model is developed. The framework guarantees the integration of the preventive protection in the system design. The validation of the design framework is executed according to a practical example. By this example, the new development of an agricultural machine that is preventively protected against imitation is shown.