The invention discloses a method for correcting power-up time of a fuel sprayer based on air inlet pressure. The method comprises the following steps of: setting a preset signal; acquiring signals; comparing the signals with the preset signal; and processing the signals. By the method, a power-up time correction factor is calculated by comparing a numerical value of actual air inlet pressure of an engine with a preset numerical value in an air inlet pressure meter, so that the power-up time of a coil of the fuel sprayer is corrected; and therefore, the fuel spraying amount of a spray orifice can be controlled accurately, so that the power performance, economy, discharging performance and safety of the engine are improved.