如果是说改游戏文件的话,在\Europa Universalis IV\common\defines.lua 里改这几行
CULTURE_COST_DIFF_ORIGINAL = -50,-- Difference in cost in percent to convert to original culture.
CULTURE_COST_DIFF_ADJACENT = -25,-- Difference in cost in percent to convert to adjacent culture.
CULTURE_COST_DIFF_PRIMARY = 0,-- Difference in cost in percent to convert to primary culture.