The invention belongs to the technical field of petroleum well cementation engineering, and specifically relates to a channeling prevention capacity evaluation device and method for cement in a simulation environment. The device formed by organically combining a constant-temperature oil groove, a cement kettle body, a gas-water kettle body, a permeation block, a heating device, a first piston, a second piston, a heating medium, a gas-water source, two electromagnetic valves, two hydraulic cylinders and a control system carries out accurate evaluation on the channeling prevention capacity of the cement by approximating to the actual working condition and through the five steps of connecting the channeling prevention capacity evaluation device for the cement in the simulation environment, heating, adding the medium into the gas-water kettle body and the cement kettle body, pressurizing, observing the channeling condition of gas or water, and calculating the channeling amount of water orgas. The channeling prevention capacity evaluation device and method for the cement in the simulation environment adopt a constant-temperature oil groove heating manner, achieve uniform heating and aconstant temperature, and facilitate to control. According to the channeling prevention capacity evaluation device and method for the cement in the simulation environment, a formation pressure is reached in the control manner of the sealed kettle bodies and the pistons, so that a more accurate experiment result is achieved; and moreover, the channeling condition in a cement weightlessness processis conveniently observed, and the channeling amount of gas or water is accurately obtained through calculation.