With finite- element method, numerical calculations of instantaneous temperature distribution in layered magneto-optical (MO) films are given. In the analysis, the emphasis is put on the ambient temperature dependence of temperature profile in layered structure, and the pulse duration dependence of minimun writing power is found at various ambient temperatures. The analysis presents an useful means to further study the characteristics of thermomagnetic recording and magneto-optical readout of MO disks used at different ambient temperatures.