The study aims to trace the management of historic assets on Penyengat Island by related parties. The search is intended to determine the application of accounting treatment to heritage assets both in terms of recognition, measurement, valuation, and presentation and disclosure. This study uses a qualitative approach. The technique of collecting data is a phenomenological paradigm approach, namely interviews, literature studies, experiments and focus group discussions (FGD). Research data analysis was carried out by applying accounting treatment to various information on historical assets on Penyengat Island. The results of the study explain that the recognition of historic assets is strengthened by parts or elements of the mosque that meet the criteria for historic assets or Cultural Heritage. Valuation of historic assets at the Great Mosque of Sultan Riau until now there is no proper model. The historical asset assessment of the mosque is still integrated with other Cultural Heritage buildings or objects on Penyengat Island. However, mosque valuation can use alternative prediction or appraisal values. Based on the results of the research and discussion that the historical asset assessment of the mosque is still integrated with other Cultural Heritage buildings or objects on Penyengat Island. However, the evaluation of mosques can use alternative prediction values orappraisal. Predictive value takes more into accountfuture economic benefit, with the potential of the mosque apart from being a place of worship as well as a potential tourist attraction.