The invention provides a method for optimizing a formula of high soluble-salt-containing pore type reservoir protection drilling fluid aiming at the serious problems of drilling fluid leakage and reservoir damage when drilling a porous reservoir rich in soluble salt. The method comprises the following steps of: measuring the pore throat distribution of reservoir core, and carrying out fluid displacement experiment for gradually reducing salinity to determine the change of core permeability with fluid salinity, and designing the salinity of drilling fluid based on that; secondly, measuring thepore throat distribution of the rock core after salt dissolution, optimizing the distribution of the solid phase particle size of the drilling fluid and ensuring that the maximum particle size of thesolid phase is slightly larger than the maximum pore throat size of the reservoir; preparing the drilling fluid, and optimizing the reservoir protection performance of the drilling fluid through indoor experiment evaluation. According to the invention, the dissolution of the drilling fluid on the soluble salt of the reservoir and the influence of the drilling fluid on the pore structure of the reservoir are fully considered, the salinity of the drilling fluid and the particle size distribution of the solid phase material are optimized, and a basis is provided for protecting the reservoir richin the soluble salt when the drilling fluid meets the pore type reservoir.