The invention discloses a parameter-adjustable intelligent high performance engine main framework. Circumferential motion of a crank is converted into reciprocation linear motion up and down of a secondary piston by a crank and rocker mechanism, a swing rod and a rocker sliding block mechanism; lateral force and resistance to a main piston and the secondary piston are smaller, and an engine is low in noise and high in heat efficiency; through a particular size relation, the size and weight of the engine are both greatly reduced; a displacement adjusting mechanism for adjusting the displacement and compression ratio of the engine cooperatively works together with other assisting systems of the engine to realize the adjustable thermodynamic cycle types of the engine. The displacement, compression ratio and thermodynamic cycle of the engine can be adjusted in real time according to the change of a load and a road condition, the engine is enabled to have well work conditions under various loads and road conditions, the energy saving and emission reduction effects of the engine are more obvious when the load is medium and small, the maximal adjusting range of the displacement of a four-cylinder engine is between 1.2 and 3.5, and the maximal adjusting range of the compression ratio of the engine is between 6 and 26.