Extension Strategic Tactics Planning (ESTP), based upon the science of extenics, is established along a perspective of solving contradictory problems. In this paper, the fundamental thoughts, theories and methods of ESTP are introduced concisely. The highlights of the paper are that the techniques, used in case of contradiction to tackle such problems as how to generate the ideas of strategic tactical planning, how to completely analyze the resources, how to exploit extension resources, how to transfer the incompatible into the compatible, and how to transfer the opposite into the co-existent, are developed in a formalized way. And regarding ESTP's practice，the applications of ESTP in resource integration, project, product innovation market development, and crisis prevention and handling are introduced.