The invention discloses a mechanism for vibration isolation of a passenger car air conditioner compressor assembly and belt stable operation. The mechanism comprises a power assembly, the compressor assembly and a car body girder; a first connection rod is installed between the power assembly and the compressor assembly and arranged in the direction of the center-to-center distance of an engine belt pulley and a transition belt pulley; a second connection rod is installed between the left side of the bottom of the compressor assembly and the car body girder, and a damping spring is installed between the right side of the bottom of the compressor assembly and the car body girder; and the second connection rod points to the center point of the transition belt pulley and is arranged in the direction perpendicular to the first connection rod. The mechanism can meet the requirement for vibration isolation of the passenger car condition compressor assembly and can also meet the requirements for belt tension and belt operation, thus, all structures of a passenger car can operate very stably, and the comfort of the passenger car is improved.