The residual temperature field of a neodymium glass laser amplifier slab after thermal recovery significantly affects beam depolarization and wavefront distortion. When asymmetry occurs during the cooling process, it causes an asymmetrical distribution of the residual temperature field, which in turn affects the repeatability of the high-power laser beam between shots. This study conducted a simulation of the residual temperature field distribution characteristics derived from weak and strong cooling applied to the cladding sides of an N41-type neodymium glass slab. Changes to the residual temperature field caused by asymmetric cooling on the cladding sides were then investigated, where the degree of change is related to the strength of cooling on the cladding sides of the neodymium glass slab. Heat dissipation on the light-passing surfaces and cladding interfaces of the neodymium glass slab was further analyzed when weak cooling transformed to strong cooling.