The invention discloses a wind power limit grid-connected capacity calculating method under the constraint of frequency modulation and peak-load regulation adequacy, and belongs to the field of power system planning operation. The method comprises the steps that a system total power fluctuation probability function covering different time scales, wind power proportion and load fluctuation under a certain degree of confidence is derived based on a power wind power fluctuation statistical model; then influence of wind power on a system frequency modulation system is quantitatively analyzed according to the maximum frequency deviation, static frequency deviation, primary/secondary frequency modulation adjustment speed and frequency modulation reserve capacity of system frequency deviation with combination of inertial response of the system and the primary/secondary frequency modulation process; and the probability of wind curtailment of the system along with increasing of wind power installation is assessed according to the power-on mode of a power system, the load fluctuation characteristic and the wind power fluctuation statistical law through consideration of factors of wind power random fluctuation and conventional machine unit random shutdown. Influence of wind power on system frequency modulation and peak-load regulation is solved by a probability method so that the power system is assisted in determining an appropriate wind power access scale within the scale of frequency modulation and peak-load regulation.