The invention provides a maximum power point tracing method and device of a photovoltaic cell. When power increment is larger than a preset power value, a constant voltage method with the quickest speed is adopted, that is, the photovoltaic cell is adjusted to output a corresponding voltage value according to a preset first duty ratio disturbance quantity. Next, integral adjustment is adopted to conduct self-adaptive adjustment to obtain a second duty ratio disturbance quantity, and an output voltage of the photovoltaic cell is adjusted according to the second duty ratio disturbance quantity so that a system can finally work at a maximum power point. Through the adoption of the constant voltage method, the searching speed is accelerated, the integral adjustment is adopted to conduct improvement on an electricity conductance increment method, the corresponding second duty ratio disturbance quantity can be directly obtained according to the error magnitude, that is, the adjustment of a step length depends on the error magnitude, and thus the purpose of balancing searching precision and searching speed can be achieved; meanwhile, through the adoption of the integral adjustment, a static error can be eliminated, and the searching precision is improved; in addition, the integral adjustment is linear, thus the stepless adjustment can be achieved, shocks are reduced, and vibrations are lowered.