The invention discloses a lithium ion battery pack modularization fast equalization circuit and an equalizing method and belongs to the field of the lithium ion battery pack modularization fast equalization circuit and the equalizing method. The lithium ion battery pack modularization fast equalization circuit and the equalizing method aim at solving the problems that the service life of a whole battery pack is short due to disequilibrium of battery cells, in series connection, in an existing lithium ion battery pack, and an existing ordinary bi-directional equalizer is long in equalizing time. According to the lithium ion battery pack modularization fast equalization circuit and the equalizing method, a lithium ion battery pack is divided into 2N three-cell battery modules, wherein each three-cell battery module is composed of three adjacent lithium ion batteries, the lithium ion battery pack further comprises 2N three-cell equilibrium sub-modules, an equilibrium main module, a switching network, N integration voltage acquisition circuit, a microcontroller, a first energy transmission bus, a second energy transmission bus, a third energy transmission bus and a fourth energy transmission bus, the switching network comprises 2N+1 switches which are M1 to M (2N+1), and the three-cell battery modules and the three-cell equilibrium sub-modules are arranged in a one-to-one corresponding mode. The lithium ion battery pack modularization fast equalization circuit and the equalizing method can be used in a series connection power battery pack.