The invention discloses a water bath device for automatic determination and stable piece taking. The water bath device comprises a water bath device body, wherein a water bath tank is formed in the water bath device body, sliding tracks are installed and arranged on two sides of the bottom of the water bath tank, a test tube stand is connected to the sliding tracks in a sliding mode, a temperature determination instrument is installed on a test tube stand body, a piece taking zone is arranged on one side of the test tube stand, a baffle body is arranged on one side of the piece taking zone, a test tube stand grabbing robot is arranged at the upper end of the piece taking zone, a pushing mechanism is further arranged on the other side of the test tube stand, the temperature determination instrument is in sensing connection with the pushing mechanism, one end of the pushing mechanism is fixed to the inner side tank wall of the water bath tank, and a push rod is led out of the other end of the pushing mechanism and is fixedly connected with the test tube stand body. In the mode, the water bath device can conduct water temperature preservation on an experimental subject, has a temperature determining function and can also take out the test tube stand to prevent the experimental subject from being damage when a certain temperature is reached.