As a unit of wage calculation, "Xi"(铱) is the product of military industry changing from military management to enterprise management, and also the outcome of military enterprises changing from supply system to wage system in the North China liberated area. It is a wartime financial management measure adopted to cope with economic difficulties as well. The implementation of "Xi" as wages maximally met the basic living needs of wartime workers and promoted the recovery and development of industry in the liberated areas. The Communist Party of China inculcated class consciousness among workers while promoting the use of "Xi" as the unit of wage calculation. The changes in the number of "Xi" are not only the concrete embodiment of the CPC's handling of the wage treatment of workers of different classes and the adjustment of labor movement policies, but also the reflection of the changes in the interest relations between labor and capital, workers and workers, and workers and farmers in the liberated areas.