He replaced him with S Anbazhagan.
The post of district secretary is an important one in the Dravidian parties' hierarchy.
Dhinakaran, engaged in a bitter tussle for power with Chief Minister K Palaniswami, had yesterday removed the latter from a party post.
The combative Dhinakaran has already removed a number of ministers and other functionaries from various positions in the AIADMK and gave them to his supporters.
He has effected a number of changes in the party structure since the merger of the factions led by Palaniswami and former chief minister O Panneerselvam on August 21.
Dhinakaran had on Saturday removed Government Chief Whip S Rajendran from the post of the party's Ariyalur district secretary days after he wrote to Assembly Speaker P Dhanapal seeking action against 19 MLAs loyal to him.
The MLAs had last week met Governor Ch Vidyasagar Rao and expressed their lack of confidence in Palaniswami, triggering demands by opposition parties, including the DMK, for a direction to the Chief Minister to prove his majority in the assembly.