The invention discloses a variable valve timing (VVT) adjusting method of an engine and a device, belonging to the technical field of the engine. The invention obtains the current work status of the engine by timely detecting the pressure change of an air inlet system and an air outlet system of the engine, modifies a VVT strategy according to the current work status of the engine, and updates the target value of the existing VVT strategy by taking a modified result as the target value of a new VVT strategy. The invention is mainly applied to the field of the engine, can dynamically adjust the VVT target value according the latest work status of the engine, and can better set the VVT strategy for the engine compared with the prior art that the VVT strategy only can be generated according to the preset target value, thereby changing the problems that the VVT strategy not only can not be best played but also can worsen the performance of the engine along with the aging of the engine in the prior art.