Abstract: A method for predicting outdoor three-dimensional space signal field strength by extended COST-231-Walfisch-Ikegami propagation model, comprising: establishing a three-dimensional scene model between a transmitting base station and a predicted region space; performing an on-site measurement according to a certain resolution in a prediction region and recording wireless signal strength information at a height of 1 m above the ground; acquiring a vertical cross section between the transmitting base station and a receiving point at a height of 1 m above the ground, and acquiring therefrom an average roof height, an average street width and an average between-building space; predicting a reception signal strength at a measurement point in a calculation formula of a COST-231-Walfishch-Ikegami propagation model; correcting the COST-231-Walfishch-Ikegami propagation model of the measurement point according to an error ? between measured data and a prediction result; acquiring a vertical cross section between the tra