In recent years, there is an effort to develop a portable, autonomous micro power generation system to obtain an order of magnitude improvement in energy density over general alkaline or lithium ion batteries. As hydrocarbon fuels have much higher energy to weight ratios than general batteries, researches to realize micro-engines fueled by such hydrocarbon fuels are carried out in some universities or institutes. The first key problem of the researches is how to get a micro-engine structure suitable for MEMS (Micro-Electro Mechanical Systems) fabrication. This micro-engine structure needs characteristics such as planar geometry, self-valving operation and a minimal number of moving parts and so on. In this paper, a micro sliding rotary type combustion engine structure is presented and described. The intrinsic characteristics of the engine housing curve named of “kindred cardioids curve” are described in details. The structural scheme and cycle process of the micro-engine are discussed. Some performance parameters of the micro engine are theoretically calculated with H2-Air mixture and specified geometry parameters. The primitive calculated results indicate that the sliding rotary combustion engine is workable and effective.