The invention relates to solar energy focusing utilization, in particular to a thermal power generating system which is used for realizing solar energy collection by solar mirrors adopting dot focusing and is applied in fixed dot array solar focusing. The thermal power generating system comprises at least one or one group of solar mirrors adopting dot focusing, at least one solar photo-thermal converter and a tracking control device, wherein the solar mirrors are arranged on a solar mirror bracket, the solar photo-thermal converters are arranged in a dotted region focused by the solar mirrors, and the focus lengths of the solar mirrors vary in the solar tracking process and are always kept in the dotted regions of the solar photo-thermal converters; and the sunlight is focused by the solar mirrors to at least one solar photo-thermal converter under the control of the tracking control device when the sunlight varies, the solar photo-thermal converters do not move with the solar mirrors in the solar tracking process of the solar mirrors, the solar photo-thermal converters are kept static relative to the ground, and the tracking and focusing utilization of solar energy is realized.