The invention discloses a pressure measurement method for a pressure chamber of an oil nozzle. The pressure measurement method comprises the steps that firstly, a fuel oil system test bed provides high-pressure fuel oil for the oil nozzle without a needle valve, and the high-pressure fuel oil is sprayed out of the oil nozzle through a nozzle hole; the jetting pressure of an inlet of the oil nozzle and the oil beam impacting force of an outlet of the nozzle hole of the oil nozzle are measured; the nozzle hole flow and the oil nozzle hole flow coefficient corresponding to the jetting pressure of the inlet of the oil nozzle are measured according to the measured data; the highest working jetting pressure of an oil sprayer is divided into n sections, and a relation function between the tested oil nozzle hole flow and the nozzle hole flow coefficient is obtained through multiple measurements; then the nozzle hole impacting force of the oil nozzle with the needle valve is measured, and the nozzle hole flow is worked out; and by means of the obtained relation function between the oil nozzle hole flow and the nozzle hole flow coefficient, the nozzle hole flow coefficient is worked out, and then the pressure of the pressure chamber is worked out. According to the pressure measurement method, the structure of the pressure chamber of the oil nozzle does not need to be changed in the measurement process, fuel oil flowing in the oil nozzle is not influenced, and the actual pressure value of the pressure chamber when the oil nozzle works can be reflected.