The invention provides a clutch pressure self-adaptive adjusting method and device for a transmission and a hydraulic automatic transmission, and relates to the technical field of automatic transmissions. The clutch pressure self-adaptation adjusting method for the transmission comprises the following steps that the acceleration change rate of an output shaft of the transmission is acquired in real time; and the pressure value of the clutch and the change rate of the pressure value are adjusted, so that the acceleration change rate is kept to be smaller than a preset acceleration change rate threshold value. According to the clutch pressure self-adaptive adjusting method and device for the transmission and the hydraulic automatic transmission, time and the slip frequency of the transmission in the action process can be effectively adjusted within a set range, meanwhile, the quality of the action process is ensured, impact, ton and dragging conditions of a vehicle in the action processof the transmission is improved, and the comfort of driving is improved.