The extension of the auditor's contract means the continuation of cooperation between the company and the auditor for a new period of time, which may also include changes in the terms and costs of the contract. The purpose of the present study was to provide a model for the extension of the auditor's contract based on the content analysis approach and according to the environmental characteristics and conditions governing the country. In this regard, according to the exploratory approach of the research and using the qualitative approach, the theme analysis method was used. The target population was 15 experts and university professors with professional experience in the field of auditing in 1402. These experts were selected based on the purposeful sampling method with the snowball approach and the interviews were continued until reaching theoretical saturation. The results of the present research show two overarching themes (factors related to audit service applicants and factors related to the supply of audit services), not the organizer theme (the degree of complexity of business and transactions, the size of the employer and the amount of effective items in the financial statements, the employer's purpose of the audit, the attitude and The characteristics of the employer's board of directors, the degree of reliance on the auditor's report, the employer's risk, compliance with the code of professional conduct, factors related to the employees working in the institutions and the level of drafting and compliance with laws and regulations) and 36 basic themes.