The invention discloses a reaction heat effect measurement device, and the device comprises a reaction still, a horizontal rotating shaft, a motor, a support, and a limiting switch. The reaction still is fixed on the horizontal rotating shaft, and is rotatably disposed on the support through the horizontal rotating shaft. One end of the horizontal rotating shaft is connected to the motor, so as to drive the reaction still to rotate. The limiting switch is in parallel connection with the motor, so as to enable the reaction still to make reciprocating rotation at certain amplitude. The invention also provides a reaction heat measurement method. According to the invention, the device can respectively heat and/or pressurize solvent to react and leached materials till the specific temperature and/pressure, and then carries out mixing and reaction, thereby achieving the measurement of reaction heat under the condition of approximate simulation of an industrialized reaction condition, solving a problem of the measurement of the leaching reaction heat effect of a complex system. Moreover, the device is simple in structure, and is wide in application range.