Michael Sata, an admirer of Zimbabwe's leader Robert Mugabe, said he would revoke licences for foreign investors if they resist his orders to give up at least a 25% stake in companies.
Sata, candidate for the Patriotic Front, said he would issue the order within one month if he wins the October 30 election.
"The statutory instrument will provide for a minimum of 25% equity, a period of five years and penalties such as cancellation of licences in the event a company does not comply," Sata said in a statement.
He said the order would apply to banks, financial institutions, mines, factories, farms and petroleum companies.
Sata, a controversial populist, two years ago called for the deportation of Chinese investors whom he accused of taking jobs from Zambians.
Zambia's presidential race is seen as a contest between Sata and acting president Rupiah Banda, who is standing on the ruling party ticket.
Others in the contest include Hakainde Hichilema of the United Party for National Development and a former vice-president Godfrey Miyanda of the Heritage Party.