Variable length connecting rod for engine

The utility model relates to a connecting rod structure connected between an engine crankshaft and a piston, in particular to a variable length connecting rod for an engine. The variable length connecting rod comprises a connecting rod big end and a connecting rod small end which are connected through the connecting rod. The variable length connecting rod is characterized by comprising a first connecting rod and a second connecting rod which are in plug-in connection with each other in the length direction and respectively connected with the connecting rod big end and the connecting rod small end; the connecting rod further comprises a driving device which applies a continuous variable driving force on the first connecting rod or the second connecting rod in order to make the first connecting rod or the second connecting rod slide relative to each other or from opposite directions along the length direction. Through the adoption of the structure, the compression ratio can be changed by adjusting the connecting rod length to adapt to the compression ratio requirements under different working conditions of the engine, so that the exhaust emission is reduced while the fuel consumption is reduced.