Establishing and improving the safeguard mechanism of high medical expenses for outpatient services is a key step toward strengthening the outpatient mutual aid mechanism. Through comparative policy analysis, this study reveals that Guangdong Province's general outpatient policy has certain advantages, which implements a zero or low deductible, the reimbursement rate generally exceeds reference cities in other provinces, or the benefit level is comparable to reference cities in other provinces. However, the annual maximum payment limits for the general outpatient pool are set lower than those in the reference cities in other provinces. Affordability assessments of the medical insurance funds show that even under the scenario featuring both high outpatient cost growth and full reimbursement, the impact of a high-cost outpatient guarantee policy on the accumulated balance of the funds remains manageable across all cities in Guangdong Province. Therefore, it is recommended that Guangdong Province implement a policy to cover high outpatient expenses across the province, with local cities setting appropriate deductible standards and reimbursement ratios. It is also recommended to continuously improve the alignment between the policy to cover high outpatient expenses and existing medical insurance policies, optimize the medical management of insured patients, enhance the outpatient service capabilities of medical institutions, actively explore suitable outpatient payment methods and other supporting policy, and strengthen the supervision of medical insurance funds to ensure efficient and coordinated policy execution.