The invention provides a rapid high-precision circuit and method realizing adaptive slope compensation. A slope generation and summation circuit, a pulse generation circuit, a dynamic bias parallel negative feedback circuit and a bleeder circuit are included; the slope generation and summation circuit generates a slope compensation voltage changing with a duty ratio; the pulse generation circuit generates narrow pulses through which charging/discharging of a capacitor is controlled via the slope current and a slope voltage is generated; the dynamic bias parallel negative feedback circuit is used to improve the speed and precision of adaptive slope compensation; and the bleeder circuit is used to generate a voltage in certain proportion to the input voltage. The adaptive slope compensationcircuit avoids harmonic oscillation caused by under-compensation and decrease of the on-load capability caused by over-compensation, the dynamic bias parallel negative feedback circuit is introduced to acceleration an adaption process, and the speed and precision of slope compensation are improved.