Introduction: Protected areas have long been considered an important tool in maintaining the integrity of habitat and species diversity. A proper understanding of the risk factors and the importance of protected areas and their effects can provide a better grounded context for preventing and dealing with these factors as well as plan and managed protected areas. Methods and materials: This study was conducted in 2015 for the environmental risk evaluation of Dena Protected Area in Sisakht county, on the basis of multi-criteria decision-making (TOPSIS) methods. Dena Protected Area, which is located in Kohgiluyeh and Boyerahmad province, is one of the richest areas in the country in terms of biodiversity and covers an area of about 93,780 hectares. In order to identify risks in the region, according to reports, field visits, interviews with experts and environmentalists and the basic information about the area, the primary risks were identified and, with the help of the Delphi questionnaire technique based on the Likert scale, the final risks facing the region were identified. Then the TOPSIS method was used to analyze and prioritize the risks identified. Using the TOPSIS method, the risks were prioritized based on three criteria (severity, probability and sensitivity of the receptors). According to the concept of ALARP, the studied risks were divided into high risk, medium risk and low risk levels. In this study, due to the number and length of categories, the risks under study were classified under five levels of risk, namely intolerable, significant, intermediate, tolerable and inconsiderable risks. Results and discussion: In the first phase, 26 risks were identified and, finally, based on the Delphi method 18 riskswere identified in the two groups of natural disasters and environmental risks (physical, biological, socio-economic and cultural risks). Analysis and prioritizing of the identified risks showed that illegal hunting was the first priority with a Proximity Coefficient of 0.905 and release of waste resulting from the presence of tourists was the least priority with a Proximity Coefficient 0.212. Based on the ranking of risks in Dena Protected Area, 11.11 percent of risks were placed in the unbearable category, 27.8 percent risks in the significant category, 16.7 percent risks in the average category, 22.2 percent and 22.2 percent risks in the category of tolerable risks were minor in this category. The main risks in the environmental sector, which covers physical, biological, socio-economic and cultural sectors, which posed the highest threat to Dena protected area were: illegal hunting under the socio-economic sector; eradication of drug crops and pasture in the biological sector; lack of support from the rangers in the country's judicial system in the cultural sector; and impacts of destructive agricultural practices of local farmers in the physical sector. Also, in the natural environmental risk sector, erosion was identified as the most important risk. Finally, management strategies to control and reduce the risks were presented. Conclusion: Results showed that the study area is not in a good condition as the result of the current management plan. It seems the best option to preserve biodiversity and ecosystem integrity is an ecosystem-based approach to integrated management and human society; if education and an explanation of these objectives be provided for the residents of the region, this can reach its goals more quickly.