The Sallary system for outsourcing workers is an important aspect in maintaining workers' welfare and creating harmonious working relationships. However, Sallary practices in some companies are often not in accordance with the principles of justice, both in terms of payment accuracy and contract transparency. This research aims to examine the Sallary system for outsourcing workers at PT Trimitra Putra Mandiri from the perspective of Islamic law. The formulation of the problem raised is how the Sallary system for outsourcing workers is applied in the company and how Islamic law reviews on Sallary system. This research uses a descriptive qualitative method on field research approach. Data collection techniques include observation, semi-structured interviews with the company and workers, and documentation data. The analysis of data technique is used inductively, by connecting the facts in the field with the relevant principles of Islamic law. Based on theory of ijarah contracts in Islam, the Sallary system must include clarity of contract, fairness of payment, and transparency in the employment contract. The results show that the Sallary system at PT Trimitra Putra Mandiri has weakness, such as late sallary, discrepancies of the amount of Sallary with the contract, and lack of transparency regarding the process of determining Sallary. The discussion reveals that this condition is not in line with the principle of justice in Islam which emphasizes the importance of good sallary payment system according to contract. This study concludes that the Sallary system at PT Trimitra Putra Mandiri needs evaluation by corporate to be in accordance with the principles of Islamic law. This improvements include increasing transparency, guaranteeing timely payment, and aligning the Sallary system with the values of social justice in Islam. The sugestion Sallary system at PT Trimitra Putra Mandiri can be harmonious, fair, and sharia-compliant.