The invention discloses a parameter self-tuning method of an SISO full-format model free controller based on partial derivative information. The partial derivative information is used as an input of aBP neural network, the BP neural network performs forward calculation and outputs a penalty factor, a step length factor and other parameters to be set of a controller through an output layer, a control algorithm of the controller is used to calculate and obtain control input for a controlled object, the gradient information of the control input for each parameter to be set is calculated, with aminimum value of a system error function as a target, a gradient descent method is used, combined with gradient information, the system error backpropagation calculation is carried out, a hidden layerweight coefficient and an output layer weight coefficient of the BP neural network are updated in real time in an online mode, and the gradient information is stored as the partial derivative information to be an input of the BP neural network of a next time. The invention provides the parameter self-tuning method of an SISO full-format model free controller based on partial derivative information, the tuning problem of the controller parameters can be effectively overcome, and a good control effect is achieved.