Abstract: This paper briefly introduces a test method of PSPC for ballast tank coatings and the test results is discussed.The results show that the cured coats have good adhesion without defects such as blister, pinhole and crack because of good physical and chemical property of epoxy coatings.The inorganic zinc silicate shop primer acts as sacrificed anode during cathodic disbanding and reduces the current demand.Undercutting from scribe and cathodic disbondment are the most important factors during PSPC test, and it is more serious for cathodic disbondment than for undercutting from scribe.The cathodic disbondment property is a key factor for a coating system to pass PSPC test.