Thermal insulation polylactide (PLA) foams with high compressive strength were successfully fabricated by combining a modified cooling batch foaming method and introduction of stereo-complex (SC) crystallites. It was found that the highest expansion ratio and the lowest thermal conductivity of pure poly(l-lactide) (PLLA) foams were 48 and 31.2 mW/(m.K), respectively. Besides a high expansion ratio, high compressive strength was important as well for thermal insulation foams but still challenging with pure PLLA foams. Therefore, SC crystallites were introduced to the matrix by mixing asymmetrical poly(d-lactide) (PDLA) and PLLA. According to scanning electron microscopy (SEM) results, SC crystallites could improve the cellular morphology and increase the expansion ratio at high foaming temperatures. The compressive performance and thermal conductivity of PLLA/PDLA foams were also investigated. PLLA/PDLA foams showed similar thermal insulation properties and largely enhanced mechanical properties compared to pure PLLA foams. In addition, the annealing process increased the crystallinity of PLA foams, which further improved their compressive properties. For foams with the same content of SC crystallites, the compressive modulus increased by 72% after annealing.