A new scheme to realize laser cooling of blocky Tm3+doped glass ZBLANP (ZrF4BaF2LaF3NaFPbF2) is proposed. In this scheme, the absorption of pumping laser power is greatly enhanced by multiple reflections between two sets of mirrors with high reflectance, and with the incident angle of the pumping laser being Brewster angle, the reflection losses on the two endfaces of the sample are reduced to nearly zero. The cooling temperature of the bulk sample and its cooling time constant in this scheme are calculated in detail, and the relationship between cooling power and number of passes with 1 W incident laser power and between sample temperature and number of passes under the different incident laser power is studied . It is found that the sample is cooled from ambient temperature (300 K) to 275.7 K, 267.4 K and 259.1 K when the incident laser power are 3 W, 4 W and 5 W respectively. Especially, when the incident laser power is 4.5 W, the sample temperature is reduced to 263.2 K, namely, the sample temperature change is 36.8 K, which is 1.53 times of that froma conventional scheme, and the corresponding cooling time constant is about 22.7 min.