The invention discloses a method for realizing traveling wave protection of an ultra-high-voltage direct-current power transmission line. The method comprises the following steps: (1) the instantaneous voltage u(t) and instantaneous current i(t) of an ultra-high-voltage direct-current power transmission line are acquired in real time to obtain the polar wave PI(t) of the ultra-high-voltage direct-current power transmission line, wherein PI(t)=Zp*i(t)-u(t), and Zp refers to polar wave impedance, time-frequency analysis is made on the polar wave PI(t) through Gabor transform to obtain the modulus value Aset of an S transform matrix, and the three-dimensional time-frequency distribution map of the S transform matrix is drawn; and (2) when Aset<Krel*Amin, a protection outlet acts, wherein Krel is reliability coefficient, Amin=Min(A<Sigma>(t)), A<Sigma>(t)=(Sigma<f=0><fs12>A(t,f)), A(t,f) is the modulus value in a Gabor transform matrix, f is frequency, t is time, fs is sampling frequency, and Amin is the minimum value of external fault and disturbance noise. By adopting the method, transient information of a line fault can be accurately grasped so as to realize traveling wave protection of an ultra-high-voltage direct-current power transmission line.