The invention relates to a fuel flow solving method for an adjustable turbopump oil supply system, and relates to the technical field of ramjet engine control. By use of the method, vent valve cornerinformation is introduced to inhibit the interference of the outside world for a flowmeter signal; the difference model of a turbopump flow regulation system is adopted to estimate a flow increment; and a previous-moment flow estimation value is adopted to serve as a basic value, and the increment and the basic value are added to serve as a model flow estimation value. The fuel flow solving methoddisclosed by the invention is combined with a Kalman filtering method, the vent valve corner information is introduced, the difference model of the turbopump flow regulation system is used for preliminarily estimating the fuel flow increment, and sensor measurement information is added to estimate the practical fuel flow, and a low-frequency-band interference signal can be effectively inhibited.