At the time of the 2006 National Census, the city's population was 3,910 in 862 households, when it was capital of the former Aslan Duz District of Parsabad County. The following census in 2011 counted 4,557 people in 1,172 households. The 2016 census measured the population of the city as 6,348 people in 1,760 households.
In 2019, the district was separated from the county in the establishment of Aslan Duz County, and Aslan Duz was transferred to the new Central District as the county's capital.
12سرشماري عمومي نفوس و مسكن 1395: استان اردبیل[General Population and Housing Census 2016: Ardabil Province]. مرکز آمار ایران [Statistical Centre of Iran] (in Persian). Archived from the original(Excel) on 22 March 2019. Retrieved 19 June 2025.
1234Jahangiri, Eshaq (26 February 2019) [تاریخ ابلاغ (Notification date) 1397/12/07 (Iranian Jalali calendar)]. تصویب نامه در خصوص تقسیمات کشوری در شهرستان پارس آباد استان اردبیل[Approval letter regarding national divisions in Parsabad County of Ardabil province]. مرکز پژوهشهای مجلس شورای اسلامی ایران [Research Center of the Islamic Consultative Assembly of Iran] (in Persian). وزارت کشور [Ministry of the Interior]. هیات وزیران [Council of Ministers]. شماره ۱۶۴۱۸۰/ت۵۵۵۱۵ه [Notification Number 164180/T55515H]. Archived from the original on 15 March 2019. Retrieved 18 June 2025.
↑Mousavi, Mir-Hossein (9 August 1987) [تاریخ تصویب (Approval date) 1366/05/18 (Iranian Jalali calendar)]. ایجاد و تشکیل تعداد 13 دهستان شامل روستاها، مزارع و مکانها در شهرستان مغان تابع استان آذربایجان شرقی[Creation and formation of 13 rural districts including villages, farms and places in Moghan County under East Azerbaijan province]. لام تا کام [Lam ta Kam] (in Persian). وزارت کشور [Ministry of the Interior]. هیات وزیران [Council of Ministers]. شناسه [ID] 519A4A8A-9894-4AA8-BDC0-B77F45FBF8F6. شماره دوره [Course number] 66, شماره جلد [Volume number] 13. Archived from the original on 18 June 2025. Retrieved 18 June 2025.
↑سرشماري عمومي نفوس و مسكن 1385: استان اردبیل[General Population and Housing Census 2006: Ardabil Province]. مرکز آمار ایران [Statistical Centre of Iran] (in Persian). Archived from the original(Excel) on 20 September 2011. Retrieved 19 June 2025.
↑Habibi, Hassan (19 June 1991) [تاریخ تصویب (Approval date) 1370/03/29 (Iranian Jalali calendar)]. ایجاد و تأسیس بخش اصلاندوز و شهرستان پارسآباد در استان آذربایجان شرقی[Creation and establishment of Aslan Duz District and Parsabad County in East Azerbaijan province]. لام تا کام [Lam ta Kam] (in Persian). وزارت کشور [Ministry of the Interior]. کمیسیون سیاسی دفاعی هیأت دولت [Political Defense Commission of the Government Board]. شناسه [ID] 85B54DBA-03C9-4E59-8DC1-BFAA78DE8AA2. شماره دوره [Course number] 70. Archived from the original on 19 June 2025. Retrieved 19 June 2025.
↑سرشماري عمومي نفوس و مسكن 1390: استان اردبیل[General Population and Housing Census 2011: Ardabil Province]. Iran Data Portal—Syracuse University (in Persian). مرکز آمار ایران [Statistical Centre of Iran]. Archived from the original(Excel) on 15 January 2023. Retrieved 19 June 2025.