There is a remittance basis of taxation. Your foreign income remitted to Malta will be taxable.
Income tax in Malta is charged on the basis of one's residency and domicile. A person who is ordinarily resident and domiciled in Malta is taxed on his or her worldwide income, with the possibility of relief against double taxation. A person who is ordinarily resident but not domiciled in Malta is taxed on income and capital gains arising in Malta and foreign-source income, excluding capital gains, remitted to Malta, subject to a minimum tax of 5,000 euros, payable irrespective of whether the foreign-sourced income is remitted to Malta or not. Where the annual foreign-sourced income of a non-domiciled person is less than 35,000, the minimum tax of 5,000 is not charged. Rather, tax is charged at the rates applicable to such person's income. Obtaining a resident permit under the MRVP or Maltese citizenship in terms of the IIP does not automatically constitute ordinary residence in Malta, but one would need to look at the time actually spent in Malta in a given year. Furthermore, becoming ordinarily resident in Malta or obtaining Maltese citizenship does not in itself alter once's domicile.
Personal income tax in Malta is dependent on residency and domicile (not citizenship). An expat relocating to Malta under one of the programs will be attaining residency (not domicile) and on that basis he is liable to taxation in Malta on any income arising in Malta and on any foreign income which is remitted (sent) to Malta. Foreign income which is not sent to Malta is not subject to tax in Malta. Foreign capital gains are also not taxable in Malta. The above is a general guidance so it is always advisable to seek advice from a tax specialist who can understand the full circumstance of the particular client.