Since normally, “税前利润” = profit before tax。 Similarly, “三费前利润” = profit before period costs / expesenses.

Period costs / expenses is an official accounting term in English. Based on Chinese accounting principles, “三费” = “期间费用” = period costs / expenses. Or, to be more clear, you could use "profit before period costs (i.e. operating expenditures, overhead, and financial expenses).

上市公司财务所表中所谓的“三费”即指营业费用、管理费用和财务费用，会计上称为期间费用……

A period cost is any cost that cannot be capitalized into prepaid expenses, inventory, or fixed assets. A period cost is more closely associated with the passage of time than with a transactional event. Since a period cost is essentially always charged to expense at once, it may more appropriately be called a period expense.