Water quality detector capable of being controlled at constant temperature

The embodiment of the utility model provides a water quality detector capable of realizing constant-temperature control. The water quality detector comprises a box body, a silicon photocell, a monochromator, a solution loader, a tungsten filament light source, a control device and a temperature regulation and control device, wherein the tungsten filament light source is arranged in the box body and is electrically connected with the control device; the monochromator is arranged in the box body and is electrically connected with the control device; the silicon photocell is arranged in the box body and is electrically connected with the control device; the solution loader is arranged in the box body; the tungsten filament light source emits light, the light is decomposed by the monochromator and then penetrates through a to-be-detected solution to be emitted to the silicon photocell, and the control device judges the concentration of the solution according to open-circuit voltage generated by the silicon photoc