As the core hot section components in gas turbine systems, the turbine blades are inevitably subjected to various microstructure creep damages after long time service, which seriously affect their service life. The hot isostatic pressing (HIP)-combined rejuvenation heat treatment process has been developed as a critical step in refurbishment of degraded blades with equiaxed structure, and there is a common view that HIP process has positive impact on healing creep cavities, however, the turbine blades in current gas turbine systems are widely made of directionally solidified superalloys with excellent resistance of creep voids due to the minimal number of oriented grain boundaries, which indicates that it is likely to use simple re-heat rejuvenation treatment consisting of solution and ageing treatments as a cheaper refurbishment method in recovering microctructures and properties of directionlly solidified superalloys. In this work, the interrupted creep test was conducted on directionlly solidified GTD111 superalloy to simulate the service damage of turbine blades. The effect of re-heat rejuvenation treatment on γ′ precipitates microstructure of creep degraded GTD111 superalloy and the evolution process of γ′ precipitates under different stages of re-heat rejuvenation treatment were investigated. The results show that solid solution treatment at the temperature range of 1180~1220 ℃ can effectively dissolve the coarsened and rafted primary γ′ precipitates and promote uniform precipitation of fine size secondary γ′ precipitates in the damaged alloy, meanwhile the size of secondary γ′ precipitates decreases with the increase of solution temperature and cooling rate. However, when the solid solution temperature increases to 1240 ℃, incipient melting in the interdendritic region ocurrs. High temperature ageing results in continued growth of the secondary γ′ precipitates and precipitation of tertiary γ′ precipitates. The size and cubic degree of the secondary γ′ precipitates increase with the increase of ageing temperature and soaking time. The tertiary γ′ precipitates continue to precipitate and grow during low temperature ageing process. The suitable re-heat rejuvenation parameters are 1220 ℃, 2 h, AC+1121 ℃, 2 h, AC+843 ℃, 24 h, AC. The rupture life of rejuvenated alloy under the condition of 750 ℃ and 843 MPa is up to 65 h, which is about 1.3 times of that of virgin alloy, due to its more volume fraction of duplex size γ′ precipitates after re-heat rejuvenation treatment.