A projector device and a heat dissipation system thereof are provided. The heat dissipation system includes a heat dissipating target chip and a heat dissipating module. The heat dissipating target chip has a bottom surface having a heat dissipating area. The heat dissipating module has a heat dissipating body and a heat passage. The heat dissipating body includes a connection end facing the bottom surface, and the heat passage extends out from the connection end and is heat exchange connected to the heat dissipating area. The heat passage has a first cross-section and a second cross-section, wherein the second cross-section is farther away to the heat dissipating area than the first cross-section. The second cross-section area is larger than the first cross-section area.