The invention relates to an engine bench automatic calibration method, device and system. The engine bench automatic calibration method comprises the steps of acquiring an engine monitoring variable and various engine state variables corresponding to an engine operating condition of an engine to be calibrated; acquiring operating condition points corresponding to the engine state variables according to a preset engine operating condition point sampling frequency; performing Gaussian process regression on the engine monitoring variable and the engine state variables to obtain a regression function model, and obtaining various engine monitoring variable values according to the regression function model and the various operating condition points; screening out the engine monitoring variable values within a preset threshold range; and calibrating the engine to be calibrated according to the operating condition points corresponding to the screened monitoring variable values. According to the invention, the operating condition points are screened through predicting the monitoring variable, so that the operating condition point exceeding the threshold range are automatically skipped, theengine is enabled to operate at a clinical operating condition stably, and real-time automatic calibration for the engine bench is achieved.