The invention relates to an adaptive protection level method under double faults of an elastic optical network, and belongs to the field of optical communications. The method comprises the following steps: S1, generating a service set, marking the service type, and initializing a network topological resource; S2, dynamically updating a Metrics value of each link in the network, and recording a proportion of spectrum resource usage on the link; S3, calculating K shortest paths for an incoming service, calculating fk(u) and loadk values of the path, and selecting a best transmission route; S4, calculating an available idle spectrum block of the transmission path, matching the available spectrum resources, and recording; S5, according to the current service type, calculating the available protection path and protection resource through an APLA algorithm, and recording the same; and S6, allocating the corresponding spectrum resource through the recorded transmission path and protection path, and returning the related path and resource information. The method in the invention avoids excessive use of resources on some links and can adaptively select protection levels according to different request types and spectrum resource usage states and ensure normal transmission of services under a condition of limited resources.