The invention relates to a method for predicting gas well bottom flow pressure, which belongs to the fields of gas well dynamic analysis and working system optimization. Including (1) measuring or collecting the casing pressure, formation depth, relative density of natural gas, reservoir temperature, gas production, natural gas compression factor, and measured gas well bottomhole pressure parameters of a certain block; (2) making a gas drilling well Underflow pressure SVM predictor; (3) Input the measured or collected parameters into the SVM predictor for self-learning to determine the key parameters of the SVM predictor, namely the kernel function parameters , insensitivity coefficient and penalty factor (4) Input the casing pressure of the well to be predicted, the middle depth of the formation, the relative density of natural gas, the reservoir temperature, the gas production rate, and the compressibility factor of natural gas into the SVM predictor to obtain the prediction result of the bottomhole flowing pressure of the gas well to be predicted. The method is accurate and efficient, and it is a new practical method for predicting the bottom hole pressure of gas wells.