Polyarylene sulfide resin and preparation method thereof

A method for preparing a polyarylene sulfide in which at least part of end groups of a main chain of the polyarylene sulfide is a hydroxyl group (—OH), wherein the polyarylene sulfide contains iodine bonded to the main chain and free iodine, and a content of the iodine bonded to the main chain and the free iodine is from 10 to 10,000 ppmw, the method including the steps of:

• polymerizing reactants including a diiodoaromatic compound and an elemental sulfur;
• and
• adding an aromatic compound having a hydroxy group thereto while carrying out the polymerization step,
• wherein the aromatic compound having the hydroxy group is added thereto when a degree of progress of the polymerization reaction is 90% or more, wherein the degree of progress of the polymerization reaction is determined by a ratio of a present viscosity to a target viscosity.