The invention provides a crankshaft assembly, a pump body assembly, a compressor and a heat pump system. The crankshaft assembly includes a crankshaft body (1), a first eccentric portion (2) and a second eccentric portion (3), wherein the first eccentric portion (2) and the second eccentric portion (3) are arranged along the crankshaft body (1) in the axial direction at intervals, and at least oneof the first eccentric portion (2) and the second eccentric portion (3) is detachably connected with the crankshaft body (1). According to the crankshaft assembly, the diameter of a center hole of apartition plate can be reduced, the sealing distance and sealing performance of the partition plate can be ensured, and the performance of the compressor can be improved.